Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1499001

Re: [RFC PATCH 00/11] Introduce writeback connectors

Show all headers | View raw

On Tue, Oct 11, 2016 at 6:25 PM, Ville Syrjälä
<ville.syrjala@linux.intel.com> wrote:
>> Writeback connector usage:
>> --------------------------
>> Due to connector routing changes being treated as "full modeset"
>> operations, any client which wishes to use a writeback connector
>> should include the connector in every modeset. The writeback will not
>> actually become active until a framebuffer is attached.
>>
>> The writeback itself is enabled by attaching a framebuffer to the
>> FB_ID property of the connector. The driver must then ensure that the
>> CRTC content of that atomic commit is written into the framebuffer.
>>
>> The writeback works in a one-shot mode with each atomic commit. This
>> prevents the same content from being written multiple times.
>> In some cases (front-buffer rendering) there might be a desire for
>> continuous operation - I think a property could be added later for
>> this kind of control.
>
> I though people agreed that this sort of thing would go through v4l.
> Continously writing to the same buffer isn't perhaps all that sensible
> anyway, and so we'd need queueing, which is what v4l has already. Well,
> I guess we might add some queueing to atomic eventually?
>
> I guess for front buffer rendering type of thing you might have some
> use for a continuous mode targeting a single fb. Though I think
> peridically triggering a new write could do as well. Of course either
> way would likely tear horribly, and having multiple buffers seems like
> the better option

Yeah, momentarily entirely forgot about v4l. I think making FB_ID
one-shot (perhaps better to call it WRITEBACK_FB_ID to avoid
confusion) is the right thing to do, and then push everything
continuous to some form of drm/v4l integration.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[RFC PATCH 00/11] Introduce writeback connectors Brian Starkey <brian.starkey@arm.com> - 2016-10-11 17:00 +0200
  [RFC PATCH 10/11] drm: mali-dp: Add support for writeback on DP550/DP650 Brian Starkey <brian.starkey@arm.com> - 2016-10-11 17:00 +0200
  [RFC PATCH 09/11] drm: mali-dp: Add RGB writeback formats for DP550/DP650 Brian Starkey <brian.starkey@arm.com> - 2016-10-11 17:00 +0200
  [RFC PATCH 02/11] drm/fb-helper: Skip writeback connectors Brian Starkey <brian.starkey@arm.com> - 2016-10-11 17:00 +0200
    Re: [RFC PATCH 02/11] drm/fb-helper: Skip writeback connectors Daniel Vetter <daniel@ffwll.ch> - 2016-10-11 17:50 +0200
      Re: [RFC PATCH 02/11] drm/fb-helper: Skip writeback connectors Brian Starkey <brian.starkey@arm.com> - 2016-10-11 18:50 +0200
        Re: [RFC PATCH 02/11] drm/fb-helper: Skip writeback connectors Daniel Vetter <daniel@ffwll.ch> - 2016-10-11 19:00 +0200
  [RFC PATCH 05/11] drm: Add fb to connector state Brian Starkey <brian.starkey@arm.com> - 2016-10-11 17:00 +0200
  [RFC PATCH 01/11] drm: Add writeback connector type Brian Starkey <brian.starkey@arm.com> - 2016-10-11 17:00 +0200
  [RFC PATCH 04/11] drm: Add __drm_framebuffer_remove_atomic Brian Starkey <brian.starkey@arm.com> - 2016-10-11 17:00 +0200
    Re: [RFC PATCH 04/11] drm: Add __drm_framebuffer_remove_atomic Daniel Vetter <daniel@ffwll.ch> - 2016-10-11 18:10 +0200
  [RFC PATCH 08/11] drm: mali-dp: Rename malidp_input_format Brian Starkey <brian.starkey@arm.com> - 2016-10-11 17:00 +0200
  [RFC PATCH 11/11] drm: mali-dp: Add writeback connector Brian Starkey <brian.starkey@arm.com> - 2016-10-11 17:00 +0200
  Re: [RFC PATCH 00/11] Introduce writeback connectors Daniel Vetter <daniel@ffwll.ch> - 2016-10-11 17:50 +0200
    Re: [RFC PATCH 00/11] Introduce writeback connectors Brian Starkey <brian.starkey@arm.com> - 2016-10-11 19:00 +0200
      Re: [RFC PATCH 00/11] Introduce writeback connectors Daniel Vetter <daniel@ffwll.ch> - 2016-10-11 19:10 +0200
        Re: [RFC PATCH 00/11] Introduce writeback connectors Brian Starkey <brian.starkey@arm.com> - 2016-10-11 21:50 +0200
          Re: [RFC PATCH 00/11] Introduce writeback connectors Daniel Vetter <daniel@ffwll.ch> - 2016-10-11 22:10 +0200
            Re: [RFC PATCH 00/11] Introduce writeback connectors Brian Starkey <brian.starkey@arm.com> - 2016-10-11 23:30 +0200
              Re: [RFC PATCH 00/11] Introduce writeback connectors Daniel Vetter <daniel@ffwll.ch> - 2016-10-12 09:00 +0200
  Re: [RFC PATCH 00/11] Introduce writeback connectors Daniel Vetter <daniel@ffwll.ch> - 2016-10-11 18:30 +0200
  Re: [RFC PATCH 00/11] Introduce writeback connectors Ville Syrjälä <ville.syrjala@linux.intel.com> - 2016-10-11 18:30 +0200
  Re: [RFC PATCH 00/11] Introduce writeback connectors Eric Anholt <eric@anholt.net> - 2016-10-11 21:10 +0200
    Re: [RFC PATCH 00/11] Introduce writeback connectors Brian Starkey <brian.starkey@arm.com> - 2016-10-12 09:40 +0200

csiph-web