[Intel-gfx] [PATCH 01/19] drm/atomic: Add new iterators over all state

[Maarten Lankhorst]

Op 01-11-16 om 14:41 schreef Ville Syrjälä:
> On Tue, Nov 01, 2016 at 02:34:00PM +0100, Maarten Lankhorst wrote:
>> Op 01-11-16 om 14:09 schreef Ville Syrjälä:
>>> On Mon, Oct 17, 2016 at 02:37:00PM +0200, Maarten Lankhorst wrote:
>>>> Add for_each_(old)(new)_(plane,connector,crtc)_in_state iterators to
>>>> replace the old for_each_xxx_in_state ones. This is useful for >1 flip
>>>> depth and getting rid of all xxx->state dereferences.
>>>>
>>>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
>>>> ---
>>>>  drivers/gpu/drm/drm_atomic.c         |  6 +++
>>>>  drivers/gpu/drm/drm_atomic_helper.c  | 52 +++++++++++++++++++++--
>>>>  drivers/gpu/drm/i915/intel_display.c | 11 ++---
>>>>  include/drm/drm_atomic.h             | 81 ++++++++++++++++++++++++++++++++++--
>>>>  include/drm/drm_atomic_helper.h      |  3 ++
>>>>  5 files changed, 142 insertions(+), 11 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
>>>> index 5dd70540219c..120775fcfb70 100644
>>>> --- a/drivers/gpu/drm/drm_atomic.c
>>>> +++ b/drivers/gpu/drm/drm_atomic.c
>>>> @@ -278,6 +278,8 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state,
>>>>  		return ERR_PTR(-ENOMEM);
>>>>  
>>>>  	state->crtcs[index].state = crtc_state;
>>>> +	state->crtcs[index].old_state = crtc->state;
>>>> +	state->crtcs[index].new_state = crtc_state;
>>>>  	state->crtcs[index].ptr = crtc;
>>>>  	crtc_state->state = state;
>>>>  
>>>> @@ -640,6 +642,8 @@ drm_atomic_get_plane_state(struct drm_atomic_state *state,
>>>>  
>>>>  	state->planes[index].state = plane_state;
>>>>  	state->planes[index].ptr = plane;
>>>> +	state->planes[index].old_state = plane->state;
>>>> +	state->planes[index].new_state = plane_state;
>>>>  	plane_state->state = state;
>>>>  
>>>>  	DRM_DEBUG_ATOMIC("Added [PLANE:%d:%s] %p state to %p\n",
>>>> @@ -931,6 +935,8 @@ drm_atomic_get_connector_state(struct drm_atomic_state *state,
>>>>  
>>>>  	drm_connector_reference(connector);
>>>>  	state->connectors[index].state = connector_state;
>>>> +	state->connectors[index].old_state = connector->state;
>>>> +	state->connectors[index].new_state = connector_state;
>>>>  	state->connectors[index].ptr = connector;
>>>>  	connector_state->state = state;
>>>>  
>>>> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
>>>> index 07b432f43b98..fcb6e5b55217 100644
>>>> --- a/drivers/gpu/drm/drm_atomic_helper.c
>>>> +++ b/drivers/gpu/drm/drm_atomic_helper.c
>>>> @@ -2495,7 +2495,7 @@ EXPORT_SYMBOL(drm_atomic_helper_disable_all);
>>>>   *
>>>>   * See also:
>>>>   * drm_atomic_helper_duplicate_state(), drm_atomic_helper_disable_all(),
>>>> - * drm_atomic_helper_resume()
>>>> + * drm_atomic_helper_resume(), drm_atomic_helper_commit_duplicated_state()
>>>>   */
>>>>  struct drm_atomic_state *drm_atomic_helper_suspend(struct drm_device *dev)
>>>>  {
>>>> @@ -2536,6 +2536,52 @@ unlock:
>>>>  EXPORT_SYMBOL(drm_atomic_helper_suspend);
>>>>  
>>>>  /**
>>>> + * drm_atomic_helper_commit_duplicated_state - commit duplicated state
>>>> + * @state: duplicated atomic state to commit
>>>> + * @ctx: pointer to acquire_ctx to use for commit.
>>>> + * @nonblock: commit the state non-blocking.
>>>> + *
>>>> + * The state returned by drm_atomic_helper_duplicate_state() and
>>>> + * drm_atomic_helper_suspend() is partially invalid, and needs to
>>>> + * be fixed up before commit.
>>> So the old_state pointers are potentially invalid because whatever->state
>>> may have changed since we duplicated the state?
>> Yes when you use drm_atomic_helper_duplicate_state, and commit a different state before committing the duplicated state.
>> This only happens during suspend/resume and gpu reset.
> Should we maybe have something like drm_atomic_refresh_old_state(state)?
> Would allow the caller then to check something in the old vs. new state
> before committing?

iirc that was the first approach I took, but then you shouldn't do anything with a duplicated state after
creating a except commit it, so creating a commit_duplicated_state should be enough.

Can you think of any case where you do the following?

Duplicate state
commit different state
Look at duplicated state, tinker with it, commit it.

~Maarten