[PATCH v2 6/6] drm/i915: Add a cursor hack to allow converting legacy page flip to atomic, v3.

[Archit Taneja]

On 12/13/2016 07:22 PM, Maarten Lankhorst wrote:
> Op 13-12-16 om 14:01 schreef Archit Taneja:
>> Hi,
>>
>> On 12/12/2016 4:04 PM, Maarten Lankhorst wrote:
>>> Do something similar to vc4, only allow updating the cursor state
>>> in-place through a fastpath when the watermarks are unaffected. This
>>> will allow cursor movement to be smooth, but changing cursor size or
>>> showing/hiding cursor will still fall back so watermarks can be updated.
>>>
>>> Only moving and changing fb is allowed.
>>
>> I was implementing something similar for msm kms. I have a comment/query
>> below.
>>
>>>
>>> Changes since v1:
>>> - Set page flip to always_unused for trybot.
>>> - Copy fence correctly, ignore plane_state->state, should be NULL.
>>> - Check crtc_state for !active and modeset, go to slowpath if the case.
>>> Changes since v2:
>>> - Make error handling work correctly. (Matthew Auld)
>>>
>>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
>>> ---
>>>  drivers/gpu/drm/i915/intel_atomic_plane.c |  47 +++++++----
>>>  drivers/gpu/drm/i915/intel_display.c      | 132 +++++++++++++++++++++++++++++-
>>>  drivers/gpu/drm/i915/intel_drv.h          |   2 +
>>>  3 files changed, 163 insertions(+), 18 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/intel_atomic_plane.c b/drivers/gpu/drm/i915/intel_atomic_plane.c
>>> index dbe9fb41ae53..60d75ce8a989 100644
>>> --- a/drivers/gpu/drm/i915/intel_atomic_plane.c
>>> +++ b/drivers/gpu/drm/i915/intel_atomic_plane.c
>>> @@ -103,36 +103,24 @@ intel_plane_destroy_state(struct drm_plane *plane,
>>>      drm_atomic_helper_plane_destroy_state(plane, state);
>>>  }
>>>
>>> -static int intel_plane_atomic_check(struct drm_plane *plane,
>>> -                    struct drm_plane_state *state)
>>> +int intel_plane_atomic_check_with_state(struct intel_crtc_state *crtc_state,
>>> +                    struct intel_plane_state *intel_state)
>>>  {
>>> +    struct drm_plane *plane = intel_state->base.plane;
>>>      struct drm_i915_private *dev_priv = to_i915(plane->dev);
>>> -    struct drm_crtc *crtc = state->crtc;
>>> -    struct intel_crtc *intel_crtc;
>>> -    struct intel_crtc_state *crtc_state;
>>> +    struct drm_plane_state *state = &intel_state->base;
>>>      struct intel_plane *intel_plane = to_intel_plane(plane);
>>> -    struct intel_plane_state *intel_state = to_intel_plane_state(state);
>>> -    struct drm_crtc_state *drm_crtc_state;
>>>      int ret;
>>>
>>> -    crtc = crtc ? crtc : plane->state->crtc;
>>> -    intel_crtc = to_intel_crtc(crtc);
>>> -
>>>      /*
>>>       * Both crtc and plane->crtc could be NULL if we're updating a
>>>       * property while the plane is disabled.  We don't actually have
>>>       * anything driver-specific we need to test in that case, so
>>>       * just return success.
>>>       */
>>> -    if (!crtc)
>>> +    if (!intel_state->base.crtc && !plane->state->crtc)
>>>          return 0;
>>>
>>> -    drm_crtc_state = drm_atomic_get_existing_crtc_state(state->state, crtc);
>>> -    if (WARN_ON(!drm_crtc_state))
>>> -        return -EINVAL;
>>> -
>>> -    crtc_state = to_intel_crtc_state(drm_crtc_state);
>>> -
>>>      /* Clip all planes to CRTC size, or 0x0 if CRTC is disabled */
>>>      intel_state->clip.x1 = 0;
>>>      intel_state->clip.y1 = 0;
>>> @@ -184,6 +172,31 @@ static int intel_plane_atomic_check(struct drm_plane *plane,
>>>      return intel_plane_atomic_calc_changes(&crtc_state->base, state);
>>>  }
>>>
>>> +static int intel_plane_atomic_check(struct drm_plane *plane,
>>> +                    struct drm_plane_state *state)
>>> +{
>>> +    struct drm_crtc *crtc = state->crtc;
>>> +    struct drm_crtc_state *drm_crtc_state;
>>> +
>>> +    crtc = crtc ? crtc : plane->state->crtc;
>>> +
>>> +    /*
>>> +     * Both crtc and plane->crtc could be NULL if we're updating a
>>> +     * property while the plane is disabled.  We don't actually have
>>> +     * anything driver-specific we need to test in that case, so
>>> +     * just return success.
>>> +     */
>>> +    if (!crtc)
>>> +        return 0;
>>> +
>>> +    drm_crtc_state = drm_atomic_get_existing_crtc_state(state->state, crtc);
>>> +    if (WARN_ON(!drm_crtc_state))
>>> +        return -EINVAL;
>>> +
>>> +    return intel_plane_atomic_check_with_state(to_intel_crtc_state(drm_crtc_state),
>>> +                           to_intel_plane_state(state));
>>> +}
>>> +
>>>  static void intel_plane_atomic_update(struct drm_plane *plane,
>>>                        struct drm_plane_state *old_state)
>>>  {
>>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>>> index 9eaf1e5bdae9..5568ecac2edc 100644
>>> --- a/drivers/gpu/drm/i915/intel_display.c
>>> +++ b/drivers/gpu/drm/i915/intel_display.c
>>> @@ -15028,6 +15028,136 @@ const struct drm_plane_funcs intel_plane_funcs = {
>>>      .atomic_destroy_state = intel_plane_destroy_state,
>>>  };
>>>
>>> +static int
>>> +intel_legacy_cursor_update(struct drm_plane *plane,
>>> +               struct drm_crtc *crtc,
>>> +               struct drm_framebuffer *fb,
>>> +               int crtc_x, int crtc_y,
>>> +               unsigned int crtc_w, unsigned int crtc_h,
>>> +               uint32_t src_x, uint32_t src_y,
>>> +               uint32_t src_w, uint32_t src_h)
>>> +{
>>> +    struct drm_i915_private *dev_priv = to_i915(crtc->dev);
>>> +    int ret;
>>> +    struct drm_plane_state *old_plane_state, *new_plane_state;
>>> +    struct intel_plane *intel_plane = to_intel_plane(plane);
>>> +    struct drm_framebuffer *old_fb;
>>> +    struct drm_crtc_state *crtc_state = crtc->state;
>>> +
>>> +    /*
>>> +     * When crtc is inactive or there is a modeset pending,
>>> +     * wait for it to complete in the slowpath
>>> +     */
>>> +    if (!crtc_state->active || needs_modeset(crtc_state) ||
>>> +        to_intel_crtc_state(crtc_state)->update_pipe)
>>> +        goto slow;
>>> +
>>> +    old_plane_state = plane->state;
>>> +
>>> +    /*
>>> +     * If any parameters change that may affect watermarks,
>>> +     * take the slowpath. Only changing fb or position should be
>>> +     * in the fastpath.
>>> +     */
>>> +    if (old_plane_state->crtc != crtc ||
>>> +        old_plane_state->src_w != src_w ||
>>> +        old_plane_state->src_h != src_h ||
>>> +        old_plane_state->crtc_w != crtc_w ||
>>> +        old_plane_state->crtc_h != crtc_h ||
>>> +        !old_plane_state->visible ||
>>> +        old_plane_state->fb->modifier != fb->modifier)
>>> +        goto slow;
>>> +
>>> +    new_plane_state = intel_plane_duplicate_state(plane);
>>> +    if (!new_plane_state)
>>> +        return -ENOMEM;
>>
>> About creating a new plane state here and swapping it later, I guess
>> it's more for the sake of intel_plane_atomic_check_with_state() to go
>> through cleanly, right? Rather than directly modifying the old plane
>> state?
> i915 keeps some derived state in intel_plane_state, we copy the full state to make sure the full derived state is updated as well.
>
>> I didn't see anything equivalent in vc4's implementation of
>> update_plane, hence was wondering why exactly it is needed.
>>
>> Also, about updating fb in the fast path, my assumption was
>> that it was only crtc_x/y was the thing most likely to be
>> changed really fast. Have you seen use cases where the fb
>> changes at a faster than vsync rate?
> It didn't cost much extra effort to implement fb changing too since that is handled in
> intel's update_plane callback too. This is why I did that as well. I'm not sure it's needed in general.
> Any changed fb still has to have the same size or we go to slowpath.

Okay, that make sense.

Thanks,
Archit

>
> ~Maarten
>

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