| Message ID | 1476266442-29803-1-git-send-email-mark.yao@rock-chips.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Oct 12, 2016 at 6:22 AM, Mark yao <mark.yao@rock-chips.com> wrote: > > I'm not familiar with the analogix driver, maybe use a power reference count > would better then direct power on/off analogix_dp. > > Does anyone has the idea to protect detect and get_modes context? > I'm not sure a reference count is going to help here. The common pattern is to call detect() followed by get_modes() and then modeset. However, it's not guaranteed that any one of those functions will be called after the other. So, if you leave things on after detect or get_modes, you might be wasting power (or worse). I recently ran into this exact problem with a panel we're using. Check out "0b8b059a7: drm/bridge: analogix_dp: Ensure the panel is properly prepared/unprepared". Perhaps you can piggyback on that function to add your pm_runtime and plat_data callbacks (since using dpms_mode might be racey). Sean > I found many other connector driver also direct access register on detect or > get_modes, no problem for it? > > On 2016年10月12日 18:00, Mark Yao wrote: > > The drm callback ->detect and ->get_modes seems is not power safe, > they may be called when device is power off, do register access on > detect or get_modes will cause system die. > > Here is the path call ->detect before analogix_dp power on > [<ffffff800843babc>] analogix_dp_detect+0x44/0xdc > [<ffffff80083fd840>] > drm_helper_probe_single_connector_modes_merge_bits+0xe8/0x41c > [<ffffff80083fdb84>] drm_helper_probe_single_connector_modes+0x10/0x18 > [<ffffff8008418d24>] drm_mode_getconnector+0xf4/0x304 > [<ffffff800840cff0>] drm_ioctl+0x23c/0x390 > [<ffffff80081a8adc>] do_vfs_ioctl+0x4b8/0x58c > [<ffffff80081a8c10>] SyS_ioctl+0x60/0x88 > > Cc: Inki Dae <inki.dae@samsung.com> > Cc: Sean Paul <seanpaul@chromium.org> > Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk> > Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com> > > Signed-off-by: Mark Yao <mark.yao@rock-chips.com> > --- > drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 28 > ++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > index efac8ab..09dece2 100644 > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > @@ -1062,6 +1062,13 @@ int analogix_dp_get_modes(struct drm_connector > *connector) > return 0; > } > > + if (dp->dpms_mode != DRM_MODE_DPMS_ON) { > + pm_runtime_get_sync(dp->dev); > + > + if (dp->plat_data->power_on) > + dp->plat_data->power_on(dp->plat_data); > + } > + > if (analogix_dp_handle_edid(dp) == 0) { > drm_mode_connector_update_edid_property(&dp->connector, edid); > num_modes += drm_add_edid_modes(&dp->connector, edid); > @@ -1073,6 +1080,13 @@ int analogix_dp_get_modes(struct drm_connector > *connector) > if (dp->plat_data->get_modes) > num_modes += dp->plat_data->get_modes(dp->plat_data, connector); > > + if (dp->dpms_mode != DRM_MODE_DPMS_ON) { > + if (dp->plat_data->power_off) > + dp->plat_data->power_off(dp->plat_data); > + > + pm_runtime_put_sync(dp->dev); > + } > + > ret = analogix_dp_prepare_panel(dp, false, false); > if (ret) > DRM_ERROR("Failed to unprepare panel (%d)\n", ret); > @@ -1106,9 +1120,23 @@ analogix_dp_detect(struct drm_connector *connector, > bool force) > return connector_status_disconnected; > } > > + if (dp->dpms_mode != DRM_MODE_DPMS_ON) { > + pm_runtime_get_sync(dp->dev); > + > + if (dp->plat_data->power_on) > + dp->plat_data->power_on(dp->plat_data); > + } > + > if (!analogix_dp_detect_hpd(dp)) > status = connector_status_connected; > > + if (dp->dpms_mode != DRM_MODE_DPMS_ON) { > + if (dp->plat_data->power_off) > + dp->plat_data->power_off(dp->plat_data); > + > + pm_runtime_put_sync(dp->dev); > + } > + > ret = analogix_dp_prepare_panel(dp, false, false); > if (ret) > DRM_ERROR("Failed to unprepare panel (%d)\n", ret); > > > > -- > Ｍark Yao
On 2016年10月12日 22:51, Sean Paul wrote: > On Wed, Oct 12, 2016 at 6:22 AM, Mark yao <mark.yao@rock-chips.com> wrote: >> I'm not familiar with the analogix driver, maybe use a power reference count >> would better then direct power on/off analogix_dp. >> >> Does anyone has the idea to protect detect and get_modes context? >> > I'm not sure a reference count is going to help here. The common > pattern is to call detect() followed by get_modes() and then modeset. > However, it's not guaranteed that any one of those functions will be > called after the other. So, if you leave things on after detect or > get_modes, you might be wasting power (or worse). > > I recently ran into this exact problem with a panel we're using. Check > out "0b8b059a7: drm/bridge: analogix_dp: Ensure the panel is properly > prepared/unprepared". Perhaps you can piggyback on that function to > add your pm_runtime and plat_data callbacks (since using dpms_mode > might be racey). > > Sean Hi Sean Thanks for your advice. I re-test the detect and get_modes, only use pm_runtime_get/put also can fix my problem. without plat_data callbacks can avoid race to dpms_mode. I had send v2 patch, you can review it. Thanks. > >> I found many other connector driver also direct access register on detect or >> get_modes, no problem for it? >> >> On 2016年10月12日 18:00, Mark Yao wrote: >> >> The drm callback ->detect and ->get_modes seems is not power safe, >> they may be called when device is power off, do register access on >> detect or get_modes will cause system die. >> >> Here is the path call ->detect before analogix_dp power on >> [<ffffff800843babc>] analogix_dp_detect+0x44/0xdc >> [<ffffff80083fd840>] >> drm_helper_probe_single_connector_modes_merge_bits+0xe8/0x41c >> [<ffffff80083fdb84>] drm_helper_probe_single_connector_modes+0x10/0x18 >> [<ffffff8008418d24>] drm_mode_getconnector+0xf4/0x304 >> [<ffffff800840cff0>] drm_ioctl+0x23c/0x390 >> [<ffffff80081a8adc>] do_vfs_ioctl+0x4b8/0x58c >> [<ffffff80081a8c10>] SyS_ioctl+0x60/0x88 >> >> Cc: Inki Dae <inki.dae@samsung.com> >> Cc: Sean Paul <seanpaul@chromium.org> >> Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk> >> Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com> >> >> Signed-off-by: Mark Yao <mark.yao@rock-chips.com> >> --- >> drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 28 >> ++++++++++++++++++++++ >> 1 file changed, 28 insertions(+) >> >> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c >> b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c >> index efac8ab..09dece2 100644 >> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c >> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c >> @@ -1062,6 +1062,13 @@ int analogix_dp_get_modes(struct drm_connector >> *connector) >> return 0; >> } >> >> + if (dp->dpms_mode != DRM_MODE_DPMS_ON) { >> + pm_runtime_get_sync(dp->dev); >> + >> + if (dp->plat_data->power_on) >> + dp->plat_data->power_on(dp->plat_data); >> + } >> + >> if (analogix_dp_handle_edid(dp) == 0) { >> drm_mode_connector_update_edid_property(&dp->connector, edid); >> num_modes += drm_add_edid_modes(&dp->connector, edid); >> @@ -1073,6 +1080,13 @@ int analogix_dp_get_modes(struct drm_connector >> *connector) >> if (dp->plat_data->get_modes) >> num_modes += dp->plat_data->get_modes(dp->plat_data, connector); >> >> + if (dp->dpms_mode != DRM_MODE_DPMS_ON) { >> + if (dp->plat_data->power_off) >> + dp->plat_data->power_off(dp->plat_data); >> + >> + pm_runtime_put_sync(dp->dev); >> + } >> + >> ret = analogix_dp_prepare_panel(dp, false, false); >> if (ret) >> DRM_ERROR("Failed to unprepare panel (%d)\n", ret); >> @@ -1106,9 +1120,23 @@ analogix_dp_detect(struct drm_connector *connector, >> bool force) >> return connector_status_disconnected; >> } >> >> + if (dp->dpms_mode != DRM_MODE_DPMS_ON) { >> + pm_runtime_get_sync(dp->dev); >> + >> + if (dp->plat_data->power_on) >> + dp->plat_data->power_on(dp->plat_data); >> + } >> + >> if (!analogix_dp_detect_hpd(dp)) >> status = connector_status_connected; >> >> + if (dp->dpms_mode != DRM_MODE_DPMS_ON) { >> + if (dp->plat_data->power_off) >> + dp->plat_data->power_off(dp->plat_data); >> + >> + pm_runtime_put_sync(dp->dev); >> + } >> + >> ret = analogix_dp_prepare_panel(dp, false, false); >> if (ret) >> DRM_ERROR("Failed to unprepare panel (%d)\n", ret); >> >> >> >> -- >> Ｍark Yao > >
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index efac8ab..09dece2 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -1062,6 +1062,13 @@ int analogix_dp_get_modes(struct drm_connector *connector) return 0; } + if (dp->dpms_mode != DRM_MODE_DPMS_ON) { + pm_runtime_get_sync(dp->dev); + + if (dp->plat_data->power_on) + dp->plat_data->power_on(dp->plat_data); + } + if (analogix_dp_handle_edid(dp) == 0) { drm_mode_connector_update_edid_property(&dp->connector, edid); num_modes += drm_add_edid_modes(&dp->connector, edid); @@ -1073,6 +1080,13 @@ int analogix_dp_get_modes(struct drm_connector *connector) if (dp->plat_data->get_modes) num_modes += dp->plat_data->get_modes(dp->plat_data, connector); + if (dp->dpms_mode != DRM_MODE_DPMS_ON) { + if (dp->plat_data->power_off) + dp->plat_data->power_off(dp->plat_data); + + pm_runtime_put_sync(dp->dev); + } + ret = analogix_dp_prepare_panel(dp, false, false); if (ret) DRM_ERROR("Failed to unprepare panel (%d)\n", ret); @@ -1106,9 +1120,23 @@ analogix_dp_detect(struct drm_connector *connector, bool force) return connector_status_disconnected; } + if (dp->dpms_mode != DRM_MODE_DPMS_ON) { + pm_runtime_get_sync(dp->dev); + + if (dp->plat_data->power_on) + dp->plat_data->power_on(dp->plat_data); + } + if (!analogix_dp_detect_hpd(dp)) status = connector_status_connected; + if (dp->dpms_mode != DRM_MODE_DPMS_ON) { + if (dp->plat_data->power_off) + dp->plat_data->power_off(dp->plat_data); + + pm_runtime_put_sync(dp->dev); + } + ret = analogix_dp_prepare_panel(dp, false, false); if (ret) DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
The drm callback ->detect and ->get_modes seems is not power safe, they may be called when device is power off, do register access on detect or get_modes will cause system die. Here is the path call ->detect before analogix_dp power on [<ffffff800843babc>] analogix_dp_detect+0x44/0xdc [<ffffff80083fd840>] drm_helper_probe_single_connector_modes_merge_bits+0xe8/0x41c [<ffffff80083fdb84>] drm_helper_probe_single_connector_modes+0x10/0x18 [<ffffff8008418d24>] drm_mode_getconnector+0xf4/0x304 [<ffffff800840cff0>] drm_ioctl+0x23c/0x390 [<ffffff80081a8adc>] do_vfs_ioctl+0x4b8/0x58c [<ffffff80081a8c10>] SyS_ioctl+0x60/0x88 Cc: Inki Dae <inki.dae@samsung.com> Cc: Sean Paul <seanpaul@chromium.org> Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk> Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com> Signed-off-by: Mark Yao <mark.yao@rock-chips.com> --- drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 28 ++++++++++++++++++++++ 1 file changed, 28 insertions(+)