| Message ID | 20221104235926.302883-2-lyude@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/2] drm/amdgpu/mst: Stop ignoring error codes and deadlocking | expand |
[Public] Thanks, Lyude! Comments inline. > -----Original Message----- > From: Lyude Paul <lyude@redhat.com> > Sent: Saturday, November 5, 2022 7:59 AM > To: amd-gfx@lists.freedesktop.org > Cc: Wentland, Harry <Harry.Wentland@amd.com>; stable@vger.kernel.org; > Li, Sun peng (Leo) <Sunpeng.Li@amd.com>; Siqueira, Rodrigo > <Rodrigo.Siqueira@amd.com>; Deucher, Alexander > <Alexander.Deucher@amd.com>; Koenig, Christian > <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>; David > Airlie <airlied@gmail.com>; Daniel Vetter <daniel@ffwll.ch>; Kazlauskas, > Nicholas <Nicholas.Kazlauskas@amd.com>; Pillai, Aurabindo > <Aurabindo.Pillai@amd.com>; Li, Roman <Roman.Li@amd.com>; Zuo, Jerry > <Jerry.Zuo@amd.com>; Wu, Hersen <hersenxs.wu@amd.com>; Lin, Wayne > <Wayne.Lin@amd.com>; Thomas Zimmermann <tzimmermann@suse.de>; > Mahfooz, Hamza <Hamza.Mahfooz@amd.com>; Hung, Alex > <Alex.Hung@amd.com>; Francis, David <David.Francis@amd.com>; Mikita > Lipski <mikita.lipski@amd.com>; Liu, Wenjing <Wenjing.Liu@amd.com>; > open list:DRM DRIVERS <dri-devel@lists.freedesktop.org>; open list <linux- > kernel@vger.kernel.org> > Subject: [PATCH 1/2] drm/amdgpu/mst: Stop ignoring error codes and > deadlocking > > It appears that amdgpu makes the mistake of completely ignoring the return > values from the DP MST helpers, and instead just returns a simple true/false. > In this case, it seems to have come back to bite us because as a result of > simply returning false from compute_mst_dsc_configs_for_state(), amdgpu > had no way of telling when a deadlock happened from these helpers. This > could definitely result in some kernel splats. > > Signed-off-by: Lyude Paul <lyude@redhat.com> > Fixes: 8c20a1ed9b4f ("drm/amd/display: MST DSC compute fair share") > Cc: Harry Wentland <harry.wentland@amd.com> > Cc: <stable@vger.kernel.org> # v5.6+ > --- > .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 18 +-- > .../display/amdgpu_dm/amdgpu_dm_mst_types.c | 107 ++++++++++------ > -- > .../display/amdgpu_dm/amdgpu_dm_mst_types.h | 12 +- > 3 files changed, 73 insertions(+), 64 deletions(-) > > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > index 0db2a88cd4d7b..6f76b2c84cdb5 100644 > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > @@ -6462,7 +6462,7 @@ static int > dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state, > struct drm_connector_state *new_con_state; > struct amdgpu_dm_connector *aconnector; > struct dm_connector_state *dm_conn_state; > - int i, j; > + int i, j, ret; > int vcpi, pbn_div, pbn, slot_num = 0; > > for_each_new_connector_in_state(state, connector, > new_con_state, i) { @@ -6509,8 +6509,11 @@ static int > dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state, > dm_conn_state->pbn = pbn; > dm_conn_state->vcpi_slots = slot_num; > > - drm_dp_mst_atomic_enable_dsc(state, aconnector- > >port, dm_conn_state->pbn, > - false); > + ret = drm_dp_mst_atomic_enable_dsc(state, > aconnector->port, > + dm_conn_state- > >pbn, false); > + if (ret != 0) > + return ret; > + > continue; > } > > @@ -9523,10 +9526,9 @@ static int amdgpu_dm_atomic_check(struct > drm_device *dev, > > #if defined(CONFIG_DRM_AMD_DC_DCN) > if (dc_resource_is_dsc_encoding_supported(dc)) { > - if (!pre_validate_dsc(state, &dm_state, vars)) { > - ret = -EINVAL; > + ret = pre_validate_dsc(state, &dm_state, vars); > + if (ret != 0) > goto fail; > - } > } > #endif > > @@ -9621,9 +9623,9 @@ static int amdgpu_dm_atomic_check(struct > drm_device *dev, > } > > #if defined(CONFIG_DRM_AMD_DC_DCN) > - if (!compute_mst_dsc_configs_for_state(state, dm_state- > >context, vars)) { > + ret = compute_mst_dsc_configs_for_state(state, dm_state- > >context, vars); > + if (ret) { > > DRM_DEBUG_DRIVER("compute_mst_dsc_configs_for_state() > failed\n"); > - ret = -EINVAL; > goto fail; > } > > diff --git > a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c > index 6ff96b4bdda5c..30bc2e5058b70 100644 > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c > +++ > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c > @@ -864,25 +864,25 @@ static bool try_disable_dsc(struct > drm_atomic_state *state, > return true; > } > > -static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state > *state, > - struct dc_state *dc_state, > - struct dc_link *dc_link, > - struct dsc_mst_fairness_vars *vars, > - struct drm_dp_mst_topology_mgr > *mgr, > - int *link_vars_start_index) > +static int compute_mst_dsc_configs_for_link(struct drm_atomic_state > *state, > + struct dc_state *dc_state, > + struct dc_link *dc_link, > + struct dsc_mst_fairness_vars *vars, > + struct drm_dp_mst_topology_mgr > *mgr, > + int *link_vars_start_index) > { > struct dc_stream_state *stream; > struct dsc_mst_fairness_params params[MAX_PIPES]; > struct amdgpu_dm_connector *aconnector; > struct drm_dp_mst_topology_state *mst_state = > drm_atomic_get_mst_topology_state(state, mgr); > int count = 0; > - int i, k; > + int i, k, ret; > bool debugfs_overwrite = false; > > memset(params, 0, sizeof(params)); > > if (IS_ERR(mst_state)) > - return false; > + return PTR_ERR(mst_state); > > mst_state->pbn_div = dm_mst_get_pbn_divider(dc_link); #if > defined(CONFIG_DRM_AMD_DC_DCN) @@ -933,7 +933,7 @@ static bool > compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, > > if (count == 0) { > ASSERT(0); > - return true; > + return 0; > } > > /* k is start index of vars for current phy link used by mst hub */ @@ > -949,11 +949,14 @@ static bool compute_mst_dsc_configs_for_link(struct > drm_atomic_state *state, > vars[i + k].bpp_x16 = 0; > if (drm_dp_atomic_find_time_slots(state, params[i].port- > >mgr, params[i].port, > vars[i + k].pbn) < 0) > - return false; > + return -EINVAL; Should we also return the error code get from drm_dp_atomic_find_time_slots() rather than assigning a new one here? > } > - if (!drm_dp_mst_atomic_check(state) && !debugfs_overwrite) { > + ret = drm_dp_mst_atomic_check(state); > + if (ret == 0 && !debugfs_overwrite) { > set_dsc_configs_from_fairness_vars(params, vars, count, k); > - return true; > + return 0; > + } else if (ret == -EDEADLK) { > + return ret; I think we should return here whenever there is an error. Not just for EDEADLK case. > } > > /* Try max compression */ > @@ -964,29 +967,30 @@ static bool > compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, > vars[i + k].bpp_x16 = > params[i].bw_range.min_target_bpp_x16; > if (drm_dp_atomic_find_time_slots(state, > params[i].port->mgr, > params[i].port, vars[i > + k].pbn) < 0) > - return false; > + return -EINVAL; Same as above. > } else { > vars[i + k].pbn = > kbps_to_peak_pbn(params[i].bw_range.stream_kbps); > vars[i + k].dsc_enabled = false; > vars[i + k].bpp_x16 = 0; > if (drm_dp_atomic_find_time_slots(state, > params[i].port->mgr, > params[i].port, vars[i > + k].pbn) < 0) > - return false; > + return -EINVAL; Same as above. > } > } > - if (drm_dp_mst_atomic_check(state)) > - return false; > + ret = drm_dp_mst_atomic_check(state); > + if (ret != 0) > + return ret; > > /* Optimize degree of compression */ > if (!increase_dsc_bpp(state, mst_state, dc_link, params, vars, count, > k)) > - return false; > + return -ENOSPC; > > if (!try_disable_dsc(state, dc_link, params, vars, count, k)) > - return false; > + return -ENOSPC; > > set_dsc_configs_from_fairness_vars(params, vars, count, k); > > - return true; > + return 0; > } > > static bool is_dsc_need_re_compute( > @@ -1087,15 +1091,16 @@ static bool is_dsc_need_re_compute( > return is_dsc_need_re_compute; > } > > -bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, > - struct dc_state *dc_state, > - struct dsc_mst_fairness_vars *vars) > +int compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, > + struct dc_state *dc_state, > + struct dsc_mst_fairness_vars *vars) > { > int i, j; > struct dc_stream_state *stream; > bool computed_streams[MAX_PIPES]; > struct amdgpu_dm_connector *aconnector; > int link_vars_start_index = 0; > + int ret = 0; > > for (i = 0; i < dc_state->stream_count; i++) > computed_streams[i] = false; > @@ -1118,17 +1123,19 @@ bool compute_mst_dsc_configs_for_state(struct > drm_atomic_state *state, > continue; > > if (dcn20_remove_stream_from_ctx(stream->ctx->dc, > dc_state, stream) != DC_OK) > - return false; > + return -EINVAL; > > if (!is_dsc_need_re_compute(state, dc_state, stream->link)) > continue; > > mutex_lock(&aconnector->mst_mgr.lock); > - if (!compute_mst_dsc_configs_for_link(state, dc_state, > stream->link, vars, > - &aconnector->mst_mgr, > - &link_vars_start_index)) { > + > + ret = compute_mst_dsc_configs_for_link(state, dc_state, > stream->link, vars, > + &aconnector->mst_mgr, > + &link_vars_start_index); > + if (ret != 0) { > mutex_unlock(&aconnector->mst_mgr.lock); > - return false; > + return ret; > } > mutex_unlock(&aconnector->mst_mgr.lock); > > @@ -1143,22 +1150,22 @@ bool compute_mst_dsc_configs_for_state(struct > drm_atomic_state *state, > > if (stream->timing.flags.DSC == 1) > if (dc_stream_add_dsc_to_resource(stream->ctx- > >dc, dc_state, stream) != DC_OK) > - return false; > + return -EINVAL; > } > > - return true; > + return ret; > } > > -static bool > - pre_compute_mst_dsc_configs_for_state(struct drm_atomic_state > *state, > - struct dc_state *dc_state, > - struct dsc_mst_fairness_vars > *vars) > +static int pre_compute_mst_dsc_configs_for_state(struct > drm_atomic_state *state, > + struct dc_state *dc_state, > + struct dsc_mst_fairness_vars > *vars) > { > int i, j; > struct dc_stream_state *stream; > bool computed_streams[MAX_PIPES]; > struct amdgpu_dm_connector *aconnector; > int link_vars_start_index = 0; > + int ret; > > for (i = 0; i < dc_state->stream_count; i++) > computed_streams[i] = false; > @@ -1184,13 +1191,12 @@ static bool > continue; > > mutex_lock(&aconnector->mst_mgr.lock); > - if (!compute_mst_dsc_configs_for_link(state, dc_state, > stream->link, vars, > - &aconnector->mst_mgr, > - &link_vars_start_index)) { > - mutex_unlock(&aconnector->mst_mgr.lock); > - return false; > - } > + ret = compute_mst_dsc_configs_for_link(state, dc_state, > stream->link, vars, > + &aconnector->mst_mgr, > + &link_vars_start_index); > mutex_unlock(&aconnector->mst_mgr.lock); > + if (ret != 0) > + return ret; > > for (j = 0; j < dc_state->stream_count; j++) { > if (dc_state->streams[j]->link == stream->link) @@ - > 1198,7 +1204,7 @@ static bool > } > } > > - return true; > + return ret; > } > > static int find_crtc_index_in_state_by_stream(struct drm_atomic_state > *state, @@ -1253,9 +1259,9 @@ static bool > is_dsc_precompute_needed(struct drm_atomic_state *state) > return ret; > } > > -bool pre_validate_dsc(struct drm_atomic_state *state, > - struct dm_atomic_state **dm_state_ptr, > - struct dsc_mst_fairness_vars *vars) > +int pre_validate_dsc(struct drm_atomic_state *state, > + struct dm_atomic_state **dm_state_ptr, > + struct dsc_mst_fairness_vars *vars) > { > int i; > struct dm_atomic_state *dm_state; > @@ -1264,11 +1270,12 @@ bool pre_validate_dsc(struct drm_atomic_state > *state, > > if (!is_dsc_precompute_needed(state)) { > DRM_INFO_ONCE("DSC precompute is not needed.\n"); > - return true; > + return 0; > } > - if (dm_atomic_get_state(state, dm_state_ptr)) { > + ret = dm_atomic_get_state(state, dm_state_ptr); > + if (ret != 0) { > DRM_INFO_ONCE("dm_atomic_get_state() failed\n"); > - return false; > + return ret; > } > dm_state = *dm_state_ptr; > > @@ -1280,7 +1287,7 @@ bool pre_validate_dsc(struct drm_atomic_state > *state, > > local_dc_state = kmemdup(dm_state->context, sizeof(struct > dc_state), GFP_KERNEL); > if (!local_dc_state) > - return false; > + return -ENOMEM; > > for (i = 0; i < local_dc_state->stream_count; i++) { > struct dc_stream_state *stream = dm_state->context- > >streams[i]; @@ -1316,9 +1323,9 @@ bool pre_validate_dsc(struct > drm_atomic_state *state, > if (ret != 0) > goto clean_exit; > > - if (!pre_compute_mst_dsc_configs_for_state(state, local_dc_state, > vars)) { > + ret = pre_compute_mst_dsc_configs_for_state(state, local_dc_state, > vars); > + if (ret != 0) { > > DRM_INFO_ONCE("pre_compute_mst_dsc_configs_for_state() > failed\n"); > - ret = -EINVAL; > goto clean_exit; > } > > @@ -1349,7 +1356,7 @@ bool pre_validate_dsc(struct drm_atomic_state > *state, > > kfree(local_dc_state); > > - return (ret == 0); > + return ret; > } > > static unsigned int kbps_from_pbn(unsigned int pbn) diff --git > a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h > index b92a7c5671aa2..97fd70df531bf 100644 > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h > +++ > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h > @@ -53,15 +53,15 @@ struct dsc_mst_fairness_vars { > struct amdgpu_dm_connector *aconnector; }; > > -bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, > - struct dc_state *dc_state, > - struct dsc_mst_fairness_vars *vars); > +int compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, > + struct dc_state *dc_state, > + struct dsc_mst_fairness_vars *vars); > > bool needs_dsc_aux_workaround(struct dc_link *link); > > -bool pre_validate_dsc(struct drm_atomic_state *state, > - struct dm_atomic_state **dm_state_ptr, > - struct dsc_mst_fairness_vars *vars); > +int pre_validate_dsc(struct drm_atomic_state *state, > + struct dm_atomic_state **dm_state_ptr, > + struct dsc_mst_fairness_vars *vars); > > enum dc_status dm_dp_mst_is_port_support_mode( > struct amdgpu_dm_connector *aconnector, > -- > 2.37.3 --- Regards, Wayne Lin
On Wed, 2022-11-09 at 09:48 +0000, Lin, Wayne wrote: > [Public] > > Thanks, Lyude! > Comments inline. > > > -----Original Message----- > > From: Lyude Paul <lyude@redhat.com> > > Sent: Saturday, November 5, 2022 7:59 AM > > To: amd-gfx@lists.freedesktop.org > > Cc: Wentland, Harry <Harry.Wentland@amd.com>; stable@vger.kernel.org; > > Li, Sun peng (Leo) <Sunpeng.Li@amd.com>; Siqueira, Rodrigo > > <Rodrigo.Siqueira@amd.com>; Deucher, Alexander > > <Alexander.Deucher@amd.com>; Koenig, Christian > > <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>; David > > Airlie <airlied@gmail.com>; Daniel Vetter <daniel@ffwll.ch>; Kazlauskas, > > Nicholas <Nicholas.Kazlauskas@amd.com>; Pillai, Aurabindo > > <Aurabindo.Pillai@amd.com>; Li, Roman <Roman.Li@amd.com>; Zuo, Jerry > > <Jerry.Zuo@amd.com>; Wu, Hersen <hersenxs.wu@amd.com>; Lin, Wayne > > <Wayne.Lin@amd.com>; Thomas Zimmermann <tzimmermann@suse.de>; > > Mahfooz, Hamza <Hamza.Mahfooz@amd.com>; Hung, Alex > > <Alex.Hung@amd.com>; Francis, David <David.Francis@amd.com>; Mikita > > Lipski <mikita.lipski@amd.com>; Liu, Wenjing <Wenjing.Liu@amd.com>; > > open list:DRM DRIVERS <dri-devel@lists.freedesktop.org>; open list <linux- > > kernel@vger.kernel.org> > > Subject: [PATCH 1/2] drm/amdgpu/mst: Stop ignoring error codes and > > deadlocking > > > > It appears that amdgpu makes the mistake of completely ignoring the return > > values from the DP MST helpers, and instead just returns a simple true/false. > > In this case, it seems to have come back to bite us because as a result of > > simply returning false from compute_mst_dsc_configs_for_state(), amdgpu > > had no way of telling when a deadlock happened from these helpers. This > > could definitely result in some kernel splats. > > > > Signed-off-by: Lyude Paul <lyude@redhat.com> > > Fixes: 8c20a1ed9b4f ("drm/amd/display: MST DSC compute fair share") > > Cc: Harry Wentland <harry.wentland@amd.com> > > Cc: <stable@vger.kernel.org> # v5.6+ > > --- > > .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 18 +-- > > .../display/amdgpu_dm/amdgpu_dm_mst_types.c | 107 ++++++++++------ > > -- > > .../display/amdgpu_dm/amdgpu_dm_mst_types.h | 12 +- > > 3 files changed, 73 insertions(+), 64 deletions(-) > > > > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > > index 0db2a88cd4d7b..6f76b2c84cdb5 100644 > > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > > @@ -6462,7 +6462,7 @@ static int > > dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state, > > struct drm_connector_state *new_con_state; > > struct amdgpu_dm_connector *aconnector; > > struct dm_connector_state *dm_conn_state; > > - int i, j; > > + int i, j, ret; > > int vcpi, pbn_div, pbn, slot_num = 0; > > > > for_each_new_connector_in_state(state, connector, > > new_con_state, i) { @@ -6509,8 +6509,11 @@ static int > > dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state, > > dm_conn_state->pbn = pbn; > > dm_conn_state->vcpi_slots = slot_num; > > > > - drm_dp_mst_atomic_enable_dsc(state, aconnector- > > > port, dm_conn_state->pbn, > > - false); > > + ret = drm_dp_mst_atomic_enable_dsc(state, > > aconnector->port, > > + dm_conn_state- > > > pbn, false); > > + if (ret != 0) > > + return ret; > > + > > continue; > > } > > > > @@ -9523,10 +9526,9 @@ static int amdgpu_dm_atomic_check(struct > > drm_device *dev, > > > > #if defined(CONFIG_DRM_AMD_DC_DCN) > > if (dc_resource_is_dsc_encoding_supported(dc)) { > > - if (!pre_validate_dsc(state, &dm_state, vars)) { > > - ret = -EINVAL; > > + ret = pre_validate_dsc(state, &dm_state, vars); > > + if (ret != 0) > > goto fail; > > - } > > } > > #endif > > > > @@ -9621,9 +9623,9 @@ static int amdgpu_dm_atomic_check(struct > > drm_device *dev, > > } > > > > #if defined(CONFIG_DRM_AMD_DC_DCN) > > - if (!compute_mst_dsc_configs_for_state(state, dm_state- > > > context, vars)) { > > + ret = compute_mst_dsc_configs_for_state(state, dm_state- > > > context, vars); > > + if (ret) { > > > > DRM_DEBUG_DRIVER("compute_mst_dsc_configs_for_state() > > failed\n"); > > - ret = -EINVAL; > > goto fail; > > } > > > > diff --git > > a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c > > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c > > index 6ff96b4bdda5c..30bc2e5058b70 100644 > > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c > > +++ > > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c > > @@ -864,25 +864,25 @@ static bool try_disable_dsc(struct > > drm_atomic_state *state, > > return true; > > } > > > > -static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state > > *state, > > - struct dc_state *dc_state, > > - struct dc_link *dc_link, > > - struct dsc_mst_fairness_vars *vars, > > - struct drm_dp_mst_topology_mgr > > *mgr, > > - int *link_vars_start_index) > > +static int compute_mst_dsc_configs_for_link(struct drm_atomic_state > > *state, > > + struct dc_state *dc_state, > > + struct dc_link *dc_link, > > + struct dsc_mst_fairness_vars *vars, > > + struct drm_dp_mst_topology_mgr > > *mgr, > > + int *link_vars_start_index) > > { > > struct dc_stream_state *stream; > > struct dsc_mst_fairness_params params[MAX_PIPES]; > > struct amdgpu_dm_connector *aconnector; > > struct drm_dp_mst_topology_state *mst_state = > > drm_atomic_get_mst_topology_state(state, mgr); > > int count = 0; > > - int i, k; > > + int i, k, ret; > > bool debugfs_overwrite = false; > > > > memset(params, 0, sizeof(params)); > > > > if (IS_ERR(mst_state)) > > - return false; > > + return PTR_ERR(mst_state); > > > > mst_state->pbn_div = dm_mst_get_pbn_divider(dc_link); #if > > defined(CONFIG_DRM_AMD_DC_DCN) @@ -933,7 +933,7 @@ static bool > > compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, > > > > if (count == 0) { > > ASSERT(0); > > - return true; > > + return 0; > > } > > > > /* k is start index of vars for current phy link used by mst hub */ @@ > > -949,11 +949,14 @@ static bool compute_mst_dsc_configs_for_link(struct > > drm_atomic_state *state, > > vars[i + k].bpp_x16 = 0; > > if (drm_dp_atomic_find_time_slots(state, params[i].port- > > > mgr, params[i].port, > > vars[i + k].pbn) < 0) > > - return false; > > + return -EINVAL; > > Should we also return the error code get from drm_dp_atomic_find_time_slots() rather than > assigning a new one here? Yes we should, nice catch! > > > } > > - if (!drm_dp_mst_atomic_check(state) && !debugfs_overwrite) { > > + ret = drm_dp_mst_atomic_check(state); > > + if (ret == 0 && !debugfs_overwrite) { > > set_dsc_configs_from_fairness_vars(params, vars, count, k); > > - return true; > > + return 0; > > + } else if (ret == -EDEADLK) { > > + return ret; > > I think we should return here whenever there is an error. Not just for EDEADLK case. sgtm > > > } > > > > /* Try max compression */ > > @@ -964,29 +967,30 @@ static bool > > compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, > > vars[i + k].bpp_x16 = > > params[i].bw_range.min_target_bpp_x16; > > if (drm_dp_atomic_find_time_slots(state, > > params[i].port->mgr, > > params[i].port, vars[i > > + k].pbn) < 0) > > - return false; > > + return -EINVAL; > > Same as above. > > > } else { > > vars[i + k].pbn = > > kbps_to_peak_pbn(params[i].bw_range.stream_kbps); > > vars[i + k].dsc_enabled = false; > > vars[i + k].bpp_x16 = 0; > > if (drm_dp_atomic_find_time_slots(state, > > params[i].port->mgr, > > params[i].port, vars[i > > + k].pbn) < 0) > > - return false; > > + return -EINVAL; > > Same as above. > > > } > > } > > - if (drm_dp_mst_atomic_check(state)) > > - return false; > > + ret = drm_dp_mst_atomic_check(state); > > + if (ret != 0) > > + return ret; > > > > /* Optimize degree of compression */ > > if (!increase_dsc_bpp(state, mst_state, dc_link, params, vars, count, > > k)) > > - return false; > > + return -ENOSPC; > > > > if (!try_disable_dsc(state, dc_link, params, vars, count, k)) > > - return false; > > + return -ENOSPC; > > > > set_dsc_configs_from_fairness_vars(params, vars, count, k); > > > > - return true; > > + return 0; > > } > > > > static bool is_dsc_need_re_compute( > > @@ -1087,15 +1091,16 @@ static bool is_dsc_need_re_compute( > > return is_dsc_need_re_compute; > > } > > > > -bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, > > - struct dc_state *dc_state, > > - struct dsc_mst_fairness_vars *vars) > > +int compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, > > + struct dc_state *dc_state, > > + struct dsc_mst_fairness_vars *vars) > > { > > int i, j; > > struct dc_stream_state *stream; > > bool computed_streams[MAX_PIPES]; > > struct amdgpu_dm_connector *aconnector; > > int link_vars_start_index = 0; > > + int ret = 0; > > > > for (i = 0; i < dc_state->stream_count; i++) > > computed_streams[i] = false; > > @@ -1118,17 +1123,19 @@ bool compute_mst_dsc_configs_for_state(struct > > drm_atomic_state *state, > > continue; > > > > if (dcn20_remove_stream_from_ctx(stream->ctx->dc, > > dc_state, stream) != DC_OK) > > - return false; > > + return -EINVAL; > > > > if (!is_dsc_need_re_compute(state, dc_state, stream->link)) > > continue; > > > > mutex_lock(&aconnector->mst_mgr.lock); > > - if (!compute_mst_dsc_configs_for_link(state, dc_state, > > stream->link, vars, > > - &aconnector->mst_mgr, > > - &link_vars_start_index)) { > > + > > + ret = compute_mst_dsc_configs_for_link(state, dc_state, > > stream->link, vars, > > + &aconnector->mst_mgr, > > + &link_vars_start_index); > > + if (ret != 0) { > > mutex_unlock(&aconnector->mst_mgr.lock); > > - return false; > > + return ret; > > } > > mutex_unlock(&aconnector->mst_mgr.lock); > > > > @@ -1143,22 +1150,22 @@ bool compute_mst_dsc_configs_for_state(struct > > drm_atomic_state *state, > > > > if (stream->timing.flags.DSC == 1) > > if (dc_stream_add_dsc_to_resource(stream->ctx- > > > dc, dc_state, stream) != DC_OK) > > - return false; > > + return -EINVAL; > > } > > > > - return true; > > + return ret; > > } > > > > -static bool > > - pre_compute_mst_dsc_configs_for_state(struct drm_atomic_state > > *state, > > - struct dc_state *dc_state, > > - struct dsc_mst_fairness_vars > > *vars) > > +static int pre_compute_mst_dsc_configs_for_state(struct > > drm_atomic_state *state, > > + struct dc_state *dc_state, > > + struct dsc_mst_fairness_vars > > *vars) > > { > > int i, j; > > struct dc_stream_state *stream; > > bool computed_streams[MAX_PIPES]; > > struct amdgpu_dm_connector *aconnector; > > int link_vars_start_index = 0; > > + int ret; > > > > for (i = 0; i < dc_state->stream_count; i++) > > computed_streams[i] = false; > > @@ -1184,13 +1191,12 @@ static bool > > continue; > > > > mutex_lock(&aconnector->mst_mgr.lock); > > - if (!compute_mst_dsc_configs_for_link(state, dc_state, > > stream->link, vars, > > - &aconnector->mst_mgr, > > - &link_vars_start_index)) { > > - mutex_unlock(&aconnector->mst_mgr.lock); > > - return false; > > - } > > + ret = compute_mst_dsc_configs_for_link(state, dc_state, > > stream->link, vars, > > + &aconnector->mst_mgr, > > + &link_vars_start_index); > > mutex_unlock(&aconnector->mst_mgr.lock); > > + if (ret != 0) > > + return ret; > > > > for (j = 0; j < dc_state->stream_count; j++) { > > if (dc_state->streams[j]->link == stream->link) @@ - > > 1198,7 +1204,7 @@ static bool > > } > > } > > > > - return true; > > + return ret; > > } > > > > static int find_crtc_index_in_state_by_stream(struct drm_atomic_state > > *state, @@ -1253,9 +1259,9 @@ static bool > > is_dsc_precompute_needed(struct drm_atomic_state *state) > > return ret; > > } > > > > -bool pre_validate_dsc(struct drm_atomic_state *state, > > - struct dm_atomic_state **dm_state_ptr, > > - struct dsc_mst_fairness_vars *vars) > > +int pre_validate_dsc(struct drm_atomic_state *state, > > + struct dm_atomic_state **dm_state_ptr, > > + struct dsc_mst_fairness_vars *vars) > > { > > int i; > > struct dm_atomic_state *dm_state; > > @@ -1264,11 +1270,12 @@ bool pre_validate_dsc(struct drm_atomic_state > > *state, > > > > if (!is_dsc_precompute_needed(state)) { > > DRM_INFO_ONCE("DSC precompute is not needed.\n"); > > - return true; > > + return 0; > > } > > - if (dm_atomic_get_state(state, dm_state_ptr)) { > > + ret = dm_atomic_get_state(state, dm_state_ptr); > > + if (ret != 0) { > > DRM_INFO_ONCE("dm_atomic_get_state() failed\n"); > > - return false; > > + return ret; > > } > > dm_state = *dm_state_ptr; > > > > @@ -1280,7 +1287,7 @@ bool pre_validate_dsc(struct drm_atomic_state > > *state, > > > > local_dc_state = kmemdup(dm_state->context, sizeof(struct > > dc_state), GFP_KERNEL); > > if (!local_dc_state) > > - return false; > > + return -ENOMEM; > > > > for (i = 0; i < local_dc_state->stream_count; i++) { > > struct dc_stream_state *stream = dm_state->context- > > > streams[i]; @@ -1316,9 +1323,9 @@ bool pre_validate_dsc(struct > > drm_atomic_state *state, > > if (ret != 0) > > goto clean_exit; > > > > - if (!pre_compute_mst_dsc_configs_for_state(state, local_dc_state, > > vars)) { > > + ret = pre_compute_mst_dsc_configs_for_state(state, local_dc_state, > > vars); > > + if (ret != 0) { > > > > DRM_INFO_ONCE("pre_compute_mst_dsc_configs_for_state() > > failed\n"); > > - ret = -EINVAL; > > goto clean_exit; > > } > > > > @@ -1349,7 +1356,7 @@ bool pre_validate_dsc(struct drm_atomic_state > > *state, > > > > kfree(local_dc_state); > > > > - return (ret == 0); > > + return ret; > > } > > > > static unsigned int kbps_from_pbn(unsigned int pbn) diff --git > > a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h > > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h > > index b92a7c5671aa2..97fd70df531bf 100644 > > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h > > +++ > > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h > > @@ -53,15 +53,15 @@ struct dsc_mst_fairness_vars { > > struct amdgpu_dm_connector *aconnector; }; > > > > -bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, > > - struct dc_state *dc_state, > > - struct dsc_mst_fairness_vars *vars); > > +int compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, > > + struct dc_state *dc_state, > > + struct dsc_mst_fairness_vars *vars); > > > > bool needs_dsc_aux_workaround(struct dc_link *link); > > > > -bool pre_validate_dsc(struct drm_atomic_state *state, > > - struct dm_atomic_state **dm_state_ptr, > > - struct dsc_mst_fairness_vars *vars); > > +int pre_validate_dsc(struct drm_atomic_state *state, > > + struct dm_atomic_state **dm_state_ptr, > > + struct dsc_mst_fairness_vars *vars); > > > > enum dc_status dm_dp_mst_is_port_support_mode( > > struct amdgpu_dm_connector *aconnector, > > -- > > 2.37.3 > --- > Regards, > Wayne Lin >
On Wed, 2022-11-09 at 09:48 +0000, Lin, Wayne wrote: > > } > > - if (!drm_dp_mst_atomic_check(state) && !debugfs_overwrite) { > > + ret = drm_dp_mst_atomic_check(state); > > + if (ret == 0 && !debugfs_overwrite) { > > set_dsc_configs_from_fairness_vars(params, vars, count, > > k); > > - return true; > > + return 0; > > + } else if (ret == -EDEADLK) { > > + return ret; > > I think we should return here whenever there is an error. Not just for > EDEADLK case. Are we sure about this one? I think we may actually want to make this so it returns on ret != -ENOSPC, since we want the function to continue if there's no space in the atomic state available so it can try recomputing things with compression enabled. On ret == 0 it should return early without doing compression, and on ret == -ENOSPC it should just continue the function from there
[Public] > -----Original Message----- > From: Lyude Paul <lyude@redhat.com> > Sent: Tuesday, November 15, 2022 5:55 AM > To: Lin, Wayne <Wayne.Lin@amd.com>; amd-gfx@lists.freedesktop.org > Cc: Wentland, Harry <Harry.Wentland@amd.com>; stable@vger.kernel.org; > Li, Sun peng (Leo) <Sunpeng.Li@amd.com>; Siqueira, Rodrigo > <Rodrigo.Siqueira@amd.com>; Deucher, Alexander > <Alexander.Deucher@amd.com>; Koenig, Christian > <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>; David > Airlie <airlied@gmail.com>; Daniel Vetter <daniel@ffwll.ch>; Kazlauskas, > Nicholas <Nicholas.Kazlauskas@amd.com>; Pillai, Aurabindo > <Aurabindo.Pillai@amd.com>; Li, Roman <Roman.Li@amd.com>; Zuo, Jerry > <Jerry.Zuo@amd.com>; Wu, Hersen <hersenxs.wu@amd.com>; Thomas > Zimmermann <tzimmermann@suse.de>; Mahfooz, Hamza > <Hamza.Mahfooz@amd.com>; Hung, Alex <Alex.Hung@amd.com>; Francis, > David <David.Francis@amd.com>; Mikita Lipski <mikita.lipski@amd.com>; Liu, > Wenjing <Wenjing.Liu@amd.com>; open list:DRM DRIVERS <dri- > devel@lists.freedesktop.org>; open list <linux-kernel@vger.kernel.org> > Subject: Re: [PATCH 1/2] drm/amdgpu/mst: Stop ignoring error codes and > deadlocking > > On Wed, 2022-11-09 at 09:48 +0000, Lin, Wayne wrote: > > > } > > > - if (!drm_dp_mst_atomic_check(state) && !debugfs_overwrite) { > > > + ret = drm_dp_mst_atomic_check(state); > > > + if (ret == 0 && !debugfs_overwrite) { > > > set_dsc_configs_from_fairness_vars(params, vars, count, k); > > > - return true; > > > + return 0; > > > + } else if (ret == -EDEADLK) { > > > + return ret; > > > > I think we should return here whenever there is an error. Not just for > > EDEADLK case. > > Are we sure about this one? I think we may actually want to make this so it > returns on ret != -ENOSPC, since we want the function to continue if there's > no space in the atomic state available so it can try recomputing things with > compression enabled. On ret == 0 it should return early without doing > compression, and on ret == -ENOSPC it should just continue the function > from there > Oh, right.. Thanks for saving me from causing disaster : ) > -- > Cheers, > Lyude Paul (she/her) > Software Engineer at Red Hat -- Regards, Wayne
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 0db2a88cd4d7b..6f76b2c84cdb5 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -6462,7 +6462,7 @@ static int dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state, struct drm_connector_state *new_con_state; struct amdgpu_dm_connector *aconnector; struct dm_connector_state *dm_conn_state; - int i, j; + int i, j, ret; int vcpi, pbn_div, pbn, slot_num = 0; for_each_new_connector_in_state(state, connector, new_con_state, i) { @@ -6509,8 +6509,11 @@ static int dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state, dm_conn_state->pbn = pbn; dm_conn_state->vcpi_slots = slot_num; - drm_dp_mst_atomic_enable_dsc(state, aconnector->port, dm_conn_state->pbn, - false); + ret = drm_dp_mst_atomic_enable_dsc(state, aconnector->port, + dm_conn_state->pbn, false); + if (ret != 0) + return ret; + continue; } @@ -9523,10 +9526,9 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev, #if defined(CONFIG_DRM_AMD_DC_DCN) if (dc_resource_is_dsc_encoding_supported(dc)) { - if (!pre_validate_dsc(state, &dm_state, vars)) { - ret = -EINVAL; + ret = pre_validate_dsc(state, &dm_state, vars); + if (ret != 0) goto fail; - } } #endif @@ -9621,9 +9623,9 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev, } #if defined(CONFIG_DRM_AMD_DC_DCN) - if (!compute_mst_dsc_configs_for_state(state, dm_state->context, vars)) { + ret = compute_mst_dsc_configs_for_state(state, dm_state->context, vars); + if (ret) { DRM_DEBUG_DRIVER("compute_mst_dsc_configs_for_state() failed\n"); - ret = -EINVAL; goto fail; } diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c index 6ff96b4bdda5c..30bc2e5058b70 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -864,25 +864,25 @@ static bool try_disable_dsc(struct drm_atomic_state *state, return true; } -static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, - struct dc_state *dc_state, - struct dc_link *dc_link, - struct dsc_mst_fairness_vars *vars, - struct drm_dp_mst_topology_mgr *mgr, - int *link_vars_start_index) +static int compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, + struct dc_state *dc_state, + struct dc_link *dc_link, + struct dsc_mst_fairness_vars *vars, + struct drm_dp_mst_topology_mgr *mgr, + int *link_vars_start_index) { struct dc_stream_state *stream; struct dsc_mst_fairness_params params[MAX_PIPES]; struct amdgpu_dm_connector *aconnector; struct drm_dp_mst_topology_state *mst_state = drm_atomic_get_mst_topology_state(state, mgr); int count = 0; - int i, k; + int i, k, ret; bool debugfs_overwrite = false; memset(params, 0, sizeof(params)); if (IS_ERR(mst_state)) - return false; + return PTR_ERR(mst_state); mst_state->pbn_div = dm_mst_get_pbn_divider(dc_link); #if defined(CONFIG_DRM_AMD_DC_DCN) @@ -933,7 +933,7 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, if (count == 0) { ASSERT(0); - return true; + return 0; } /* k is start index of vars for current phy link used by mst hub */ @@ -949,11 +949,14 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, vars[i + k].bpp_x16 = 0; if (drm_dp_atomic_find_time_slots(state, params[i].port->mgr, params[i].port, vars[i + k].pbn) < 0) - return false; + return -EINVAL; } - if (!drm_dp_mst_atomic_check(state) && !debugfs_overwrite) { + ret = drm_dp_mst_atomic_check(state); + if (ret == 0 && !debugfs_overwrite) { set_dsc_configs_from_fairness_vars(params, vars, count, k); - return true; + return 0; + } else if (ret == -EDEADLK) { + return ret; } /* Try max compression */ @@ -964,29 +967,30 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, vars[i + k].bpp_x16 = params[i].bw_range.min_target_bpp_x16; if (drm_dp_atomic_find_time_slots(state, params[i].port->mgr, params[i].port, vars[i + k].pbn) < 0) - return false; + return -EINVAL; } else { vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps); vars[i + k].dsc_enabled = false; vars[i + k].bpp_x16 = 0; if (drm_dp_atomic_find_time_slots(state, params[i].port->mgr, params[i].port, vars[i + k].pbn) < 0) - return false; + return -EINVAL; } } - if (drm_dp_mst_atomic_check(state)) - return false; + ret = drm_dp_mst_atomic_check(state); + if (ret != 0) + return ret; /* Optimize degree of compression */ if (!increase_dsc_bpp(state, mst_state, dc_link, params, vars, count, k)) - return false; + return -ENOSPC; if (!try_disable_dsc(state, dc_link, params, vars, count, k)) - return false; + return -ENOSPC; set_dsc_configs_from_fairness_vars(params, vars, count, k); - return true; + return 0; } static bool is_dsc_need_re_compute( @@ -1087,15 +1091,16 @@ static bool is_dsc_need_re_compute( return is_dsc_need_re_compute; } -bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, - struct dc_state *dc_state, - struct dsc_mst_fairness_vars *vars) +int compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, + struct dc_state *dc_state, + struct dsc_mst_fairness_vars *vars) { int i, j; struct dc_stream_state *stream; bool computed_streams[MAX_PIPES]; struct amdgpu_dm_connector *aconnector; int link_vars_start_index = 0; + int ret = 0; for (i = 0; i < dc_state->stream_count; i++) computed_streams[i] = false; @@ -1118,17 +1123,19 @@ bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, continue; if (dcn20_remove_stream_from_ctx(stream->ctx->dc, dc_state, stream) != DC_OK) - return false; + return -EINVAL; if (!is_dsc_need_re_compute(state, dc_state, stream->link)) continue; mutex_lock(&aconnector->mst_mgr.lock); - if (!compute_mst_dsc_configs_for_link(state, dc_state, stream->link, vars, - &aconnector->mst_mgr, - &link_vars_start_index)) { + + ret = compute_mst_dsc_configs_for_link(state, dc_state, stream->link, vars, + &aconnector->mst_mgr, + &link_vars_start_index); + if (ret != 0) { mutex_unlock(&aconnector->mst_mgr.lock); - return false; + return ret; } mutex_unlock(&aconnector->mst_mgr.lock); @@ -1143,22 +1150,22 @@ bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, if (stream->timing.flags.DSC == 1) if (dc_stream_add_dsc_to_resource(stream->ctx->dc, dc_state, stream) != DC_OK) - return false; + return -EINVAL; } - return true; + return ret; } -static bool - pre_compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, - struct dc_state *dc_state, - struct dsc_mst_fairness_vars *vars) +static int pre_compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, + struct dc_state *dc_state, + struct dsc_mst_fairness_vars *vars) { int i, j; struct dc_stream_state *stream; bool computed_streams[MAX_PIPES]; struct amdgpu_dm_connector *aconnector; int link_vars_start_index = 0; + int ret; for (i = 0; i < dc_state->stream_count; i++) computed_streams[i] = false; @@ -1184,13 +1191,12 @@ static bool continue; mutex_lock(&aconnector->mst_mgr.lock); - if (!compute_mst_dsc_configs_for_link(state, dc_state, stream->link, vars, - &aconnector->mst_mgr, - &link_vars_start_index)) { - mutex_unlock(&aconnector->mst_mgr.lock); - return false; - } + ret = compute_mst_dsc_configs_for_link(state, dc_state, stream->link, vars, + &aconnector->mst_mgr, + &link_vars_start_index); mutex_unlock(&aconnector->mst_mgr.lock); + if (ret != 0) + return ret; for (j = 0; j < dc_state->stream_count; j++) { if (dc_state->streams[j]->link == stream->link) @@ -1198,7 +1204,7 @@ static bool } } - return true; + return ret; } static int find_crtc_index_in_state_by_stream(struct drm_atomic_state *state, @@ -1253,9 +1259,9 @@ static bool is_dsc_precompute_needed(struct drm_atomic_state *state) return ret; } -bool pre_validate_dsc(struct drm_atomic_state *state, - struct dm_atomic_state **dm_state_ptr, - struct dsc_mst_fairness_vars *vars) +int pre_validate_dsc(struct drm_atomic_state *state, + struct dm_atomic_state **dm_state_ptr, + struct dsc_mst_fairness_vars *vars) { int i; struct dm_atomic_state *dm_state; @@ -1264,11 +1270,12 @@ bool pre_validate_dsc(struct drm_atomic_state *state, if (!is_dsc_precompute_needed(state)) { DRM_INFO_ONCE("DSC precompute is not needed.\n"); - return true; + return 0; } - if (dm_atomic_get_state(state, dm_state_ptr)) { + ret = dm_atomic_get_state(state, dm_state_ptr); + if (ret != 0) { DRM_INFO_ONCE("dm_atomic_get_state() failed\n"); - return false; + return ret; } dm_state = *dm_state_ptr; @@ -1280,7 +1287,7 @@ bool pre_validate_dsc(struct drm_atomic_state *state, local_dc_state = kmemdup(dm_state->context, sizeof(struct dc_state), GFP_KERNEL); if (!local_dc_state) - return false; + return -ENOMEM; for (i = 0; i < local_dc_state->stream_count; i++) { struct dc_stream_state *stream = dm_state->context->streams[i]; @@ -1316,9 +1323,9 @@ bool pre_validate_dsc(struct drm_atomic_state *state, if (ret != 0) goto clean_exit; - if (!pre_compute_mst_dsc_configs_for_state(state, local_dc_state, vars)) { + ret = pre_compute_mst_dsc_configs_for_state(state, local_dc_state, vars); + if (ret != 0) { DRM_INFO_ONCE("pre_compute_mst_dsc_configs_for_state() failed\n"); - ret = -EINVAL; goto clean_exit; } @@ -1349,7 +1356,7 @@ bool pre_validate_dsc(struct drm_atomic_state *state, kfree(local_dc_state); - return (ret == 0); + return ret; } static unsigned int kbps_from_pbn(unsigned int pbn) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h index b92a7c5671aa2..97fd70df531bf 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h @@ -53,15 +53,15 @@ struct dsc_mst_fairness_vars { struct amdgpu_dm_connector *aconnector; }; -bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, - struct dc_state *dc_state, - struct dsc_mst_fairness_vars *vars); +int compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, + struct dc_state *dc_state, + struct dsc_mst_fairness_vars *vars); bool needs_dsc_aux_workaround(struct dc_link *link); -bool pre_validate_dsc(struct drm_atomic_state *state, - struct dm_atomic_state **dm_state_ptr, - struct dsc_mst_fairness_vars *vars); +int pre_validate_dsc(struct drm_atomic_state *state, + struct dm_atomic_state **dm_state_ptr, + struct dsc_mst_fairness_vars *vars); enum dc_status dm_dp_mst_is_port_support_mode( struct amdgpu_dm_connector *aconnector,
It appears that amdgpu makes the mistake of completely ignoring the return values from the DP MST helpers, and instead just returns a simple true/false. In this case, it seems to have come back to bite us because as a result of simply returning false from compute_mst_dsc_configs_for_state(), amdgpu had no way of telling when a deadlock happened from these helpers. This could definitely result in some kernel splats. Signed-off-by: Lyude Paul <lyude@redhat.com> Fixes: 8c20a1ed9b4f ("drm/amd/display: MST DSC compute fair share") Cc: Harry Wentland <harry.wentland@amd.com> Cc: <stable@vger.kernel.org> # v5.6+ --- .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 18 +-- .../display/amdgpu_dm/amdgpu_dm_mst_types.c | 107 ++++++++++-------- .../display/amdgpu_dm/amdgpu_dm_mst_types.h | 12 +- 3 files changed, 73 insertions(+), 64 deletions(-)