| Message ID | 20250115-bridge-connector-v1-1-9a2fecd886a6@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | drm/bridge: Various quality of life improvements | expand |
On Wed, Jan 15, 2025 at 10:05:08PM +0100, Maxime Ripard wrote: > Even though the commit_tail () drm_atomic_state parameter is called > old_state, it's actually the state being committed which is confusing. > > It's even more confusing since the atomic_commit_tail hook being called > by commit_tail() parameter is called state. Do you have any kind of history and/or explanation, why it's called old_state all over the place? I think that the renaming is correct, but I'd like to understand the reason behind it. > Let's rename the variable from old_state to state to make it less > confusing. > > Signed-off-by: Maxime Ripard <mripard@kernel.org> > --- > drivers/gpu/drm/drm_atomic_helper.c | 20 ++++++++++---------- > 1 file changed, 10 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > index 40e4e1b6c9110677c1c4981eeb15dc93966f4cf6..913d94d664d885323ad7e41a6424633c28c787e1 100644 > --- a/drivers/gpu/drm/drm_atomic_helper.c > +++ b/drivers/gpu/drm/drm_atomic_helper.c > @@ -1818,13 +1818,13 @@ void drm_atomic_helper_commit_tail_rpm(struct drm_atomic_state *old_state) > > drm_atomic_helper_cleanup_planes(dev, old_state); > } > EXPORT_SYMBOL(drm_atomic_helper_commit_tail_rpm); > > -static void commit_tail(struct drm_atomic_state *old_state) > +static void commit_tail(struct drm_atomic_state *state) > { > - struct drm_device *dev = old_state->dev; > + struct drm_device *dev = state->dev; > const struct drm_mode_config_helper_funcs *funcs; > struct drm_crtc_state *new_crtc_state; > struct drm_crtc *crtc; > ktime_t start; > s64 commit_time_ms; > @@ -1842,37 +1842,37 @@ static void commit_tail(struct drm_atomic_state *old_state) > * These times will be averaged out in the self refresh helpers to avoid > * overreacting over one outlier frame > */ > start = ktime_get(); > > - drm_atomic_helper_wait_for_fences(dev, old_state, false); > + drm_atomic_helper_wait_for_fences(dev, state, false); > > - drm_atomic_helper_wait_for_dependencies(old_state); > + drm_atomic_helper_wait_for_dependencies(state); > > /* > * We cannot safely access new_crtc_state after > * drm_atomic_helper_commit_hw_done() so figure out which crtc's have > * self-refresh active beforehand: > */ > - for_each_new_crtc_in_state(old_state, crtc, new_crtc_state, i) > + for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) > if (new_crtc_state->self_refresh_active) > new_self_refresh_mask |= BIT(i); > > if (funcs && funcs->atomic_commit_tail) > - funcs->atomic_commit_tail(old_state); > + funcs->atomic_commit_tail(state); > else > - drm_atomic_helper_commit_tail(old_state); > + drm_atomic_helper_commit_tail(state); > > commit_time_ms = ktime_ms_delta(ktime_get(), start); > if (commit_time_ms > 0) > - drm_self_refresh_helper_update_avg_times(old_state, > + drm_self_refresh_helper_update_avg_times(state, > (unsigned long)commit_time_ms, > new_self_refresh_mask); > > - drm_atomic_helper_commit_cleanup_done(old_state); > + drm_atomic_helper_commit_cleanup_done(state); > > - drm_atomic_state_put(old_state); > + drm_atomic_state_put(state); > } > > static void commit_work(struct work_struct *work) > { > struct drm_atomic_state *state = container_of(work, > > -- > 2.47.1 >
On Thu, Jan 16, 2025 at 03:36:12AM +0200, Dmitry Baryshkov wrote: > On Wed, Jan 15, 2025 at 10:05:08PM +0100, Maxime Ripard wrote: > > Even though the commit_tail () drm_atomic_state parameter is called > > old_state, it's actually the state being committed which is confusing. > > > > It's even more confusing since the atomic_commit_tail hook being called > > by commit_tail() parameter is called state. > > Do you have any kind of history and/or explanation, why it's called > old_state all over the place? > > I think that the renaming is correct, but I'd like to understand the > reason behind it. So originally drm_atomic_state only had a single set of state pointers, so was truly just a state collection and not a state transition/commit like it is now. During atomic check it contained the new states, and the old ones you could get by looking at obj->state pointers. After drm_atomic_helper_swap_state it contained the old states, and the new ones could be found by looking at obj->state. This caused endless amounts of confusions, and eventually we settled on a new design: - Ville added both old and new state pointers to drm_atomic_state, so now it's not just a state collection, but really a state transition/commit. We did discuss whether we should also rename it, but for lack of time and good name this hasn't happened yet. - Instead of trying to pass the individual states to callbacks we've moved over to just passing drm_atomic_state, and let the callbacks grab whatever they need. That's also not yet done everywhere yet, but I think we're pretty close. But one of the interim attempts at reducing the confusion was to rename the drm_atomic_state argument to old_state anywhere after we've called swap_states(). Didn't really help, and not it's just adding to the confusion. If we haven't yet I guess we should document the above two design principles in the drm_atomic_state kerneldoc. Cheers, Sima > > > Let's rename the variable from old_state to state to make it less > > confusing. > > > > Signed-off-by: Maxime Ripard <mripard@kernel.org> > > --- > > drivers/gpu/drm/drm_atomic_helper.c | 20 ++++++++++---------- > > 1 file changed, 10 insertions(+), 10 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > > index 40e4e1b6c9110677c1c4981eeb15dc93966f4cf6..913d94d664d885323ad7e41a6424633c28c787e1 100644 > > --- a/drivers/gpu/drm/drm_atomic_helper.c > > +++ b/drivers/gpu/drm/drm_atomic_helper.c > > @@ -1818,13 +1818,13 @@ void drm_atomic_helper_commit_tail_rpm(struct drm_atomic_state *old_state) > > > > drm_atomic_helper_cleanup_planes(dev, old_state); > > } > > EXPORT_SYMBOL(drm_atomic_helper_commit_tail_rpm); > > > > -static void commit_tail(struct drm_atomic_state *old_state) > > +static void commit_tail(struct drm_atomic_state *state) > > { > > - struct drm_device *dev = old_state->dev; > > + struct drm_device *dev = state->dev; > > const struct drm_mode_config_helper_funcs *funcs; > > struct drm_crtc_state *new_crtc_state; > > struct drm_crtc *crtc; > > ktime_t start; > > s64 commit_time_ms; > > @@ -1842,37 +1842,37 @@ static void commit_tail(struct drm_atomic_state *old_state) > > * These times will be averaged out in the self refresh helpers to avoid > > * overreacting over one outlier frame > > */ > > start = ktime_get(); > > > > - drm_atomic_helper_wait_for_fences(dev, old_state, false); > > + drm_atomic_helper_wait_for_fences(dev, state, false); > > > > - drm_atomic_helper_wait_for_dependencies(old_state); > > + drm_atomic_helper_wait_for_dependencies(state); > > > > /* > > * We cannot safely access new_crtc_state after > > * drm_atomic_helper_commit_hw_done() so figure out which crtc's have > > * self-refresh active beforehand: > > */ > > - for_each_new_crtc_in_state(old_state, crtc, new_crtc_state, i) > > + for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) > > if (new_crtc_state->self_refresh_active) > > new_self_refresh_mask |= BIT(i); > > > > if (funcs && funcs->atomic_commit_tail) > > - funcs->atomic_commit_tail(old_state); > > + funcs->atomic_commit_tail(state); > > else > > - drm_atomic_helper_commit_tail(old_state); > > + drm_atomic_helper_commit_tail(state); > > > > commit_time_ms = ktime_ms_delta(ktime_get(), start); > > if (commit_time_ms > 0) > > - drm_self_refresh_helper_update_avg_times(old_state, > > + drm_self_refresh_helper_update_avg_times(state, > > (unsigned long)commit_time_ms, > > new_self_refresh_mask); > > > > - drm_atomic_helper_commit_cleanup_done(old_state); > > + drm_atomic_helper_commit_cleanup_done(state); > > > > - drm_atomic_state_put(old_state); > > + drm_atomic_state_put(state); > > } > > > > static void commit_work(struct work_struct *work) > > { > > struct drm_atomic_state *state = container_of(work, > > > > -- > > 2.47.1 > > > > -- > With best wishes > Dmitry
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 40e4e1b6c9110677c1c4981eeb15dc93966f4cf6..913d94d664d885323ad7e41a6424633c28c787e1 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -1818,13 +1818,13 @@ void drm_atomic_helper_commit_tail_rpm(struct drm_atomic_state *old_state) drm_atomic_helper_cleanup_planes(dev, old_state); } EXPORT_SYMBOL(drm_atomic_helper_commit_tail_rpm); -static void commit_tail(struct drm_atomic_state *old_state) +static void commit_tail(struct drm_atomic_state *state) { - struct drm_device *dev = old_state->dev; + struct drm_device *dev = state->dev; const struct drm_mode_config_helper_funcs *funcs; struct drm_crtc_state *new_crtc_state; struct drm_crtc *crtc; ktime_t start; s64 commit_time_ms; @@ -1842,37 +1842,37 @@ static void commit_tail(struct drm_atomic_state *old_state) * These times will be averaged out in the self refresh helpers to avoid * overreacting over one outlier frame */ start = ktime_get(); - drm_atomic_helper_wait_for_fences(dev, old_state, false); + drm_atomic_helper_wait_for_fences(dev, state, false); - drm_atomic_helper_wait_for_dependencies(old_state); + drm_atomic_helper_wait_for_dependencies(state); /* * We cannot safely access new_crtc_state after * drm_atomic_helper_commit_hw_done() so figure out which crtc's have * self-refresh active beforehand: */ - for_each_new_crtc_in_state(old_state, crtc, new_crtc_state, i) + for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) if (new_crtc_state->self_refresh_active) new_self_refresh_mask |= BIT(i); if (funcs && funcs->atomic_commit_tail) - funcs->atomic_commit_tail(old_state); + funcs->atomic_commit_tail(state); else - drm_atomic_helper_commit_tail(old_state); + drm_atomic_helper_commit_tail(state); commit_time_ms = ktime_ms_delta(ktime_get(), start); if (commit_time_ms > 0) - drm_self_refresh_helper_update_avg_times(old_state, + drm_self_refresh_helper_update_avg_times(state, (unsigned long)commit_time_ms, new_self_refresh_mask); - drm_atomic_helper_commit_cleanup_done(old_state); + drm_atomic_helper_commit_cleanup_done(state); - drm_atomic_state_put(old_state); + drm_atomic_state_put(state); } static void commit_work(struct work_struct *work) { struct drm_atomic_state *state = container_of(work,
Even though the commit_tail () drm_atomic_state parameter is called old_state, it's actually the state being committed which is confusing. It's even more confusing since the atomic_commit_tail hook being called by commit_tail() parameter is called state. Let's rename the variable from old_state to state to make it less confusing. Signed-off-by: Maxime Ripard <mripard@kernel.org> --- drivers/gpu/drm/drm_atomic_helper.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)