All of lore.kernel.org
 help / color / mirror / Atom feed
From: Fabio Piparo <holofermes@gmail.com>
To: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Javier Martinez Canillas <javierm@redhat.com>,
	dri-devel@lists.freedesktop.org,
	Fabio Piparo <holofermes@gmail.com>
Subject: Re: drm/ssd130x: stale pixels when the GPU renders into the framebuffer
Date: Wed, 23 Sep 2026 12:00:49 -0400	[thread overview]
Message-ID: <20260923160049.1741651-1-holofermes@gmail.com> (raw)
In-Reply-To: <1f383114-e367-4b67-899b-14a393fece94@suse.de>

Hi Thomas,

Thanks for taking a look.

On 14.09.26 10:43, Thomas Zimmermann wrote:
> I assume you write these frames quickly one after the other? As i2c is
> really slow, you might write to buffers that are still being transferred
> in the background.
>
> Do you read back the status of the page flips? DRM should tell you when
> it has completed transferring a frame. See [1]

The test renders with the GPU: two dumb buffers allocated on the
ssd130x device and shared with v3d over PRIME. It runs at 10 fps.
Before each flip it calls glFinish(), then flips with
DRM_MODE_PAGE_FLIP_EVENT and waits for the event before drawing into
the other buffer. The same test drawing with the CPU instead comes out
clean.

I'm happy to send the test program if it would help.

Best regards,
Fabio

  reply	other threads:[~2026-09-25  7:30 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-13  4:27 drm/ssd130x: stale pixels when the GPU renders into the framebuffer Fabio Piparo
2026-08-14 18:34 ` Javier Martinez Canillas
2026-09-14  8:43 ` Thomas Zimmermann
2026-09-23 16:00   ` Fabio Piparo [this message]
2026-09-29  9:04     ` Thomas Zimmermann
2026-09-29 21:50       ` Maíra Canal
2026-09-30  6:48         ` Thomas Zimmermann
2026-09-30  7:48           ` Javier Martinez Canillas
2026-09-30  8:32             ` Thomas Zimmermann
2026-09-30 13:49               ` Maíra Canal
2026-09-30 15:52                 ` Javier Martinez Canillas
2026-09-30 18:45                   ` Fabio Piparo
2026-10-02  8:18                     ` Thomas Zimmermann
2026-09-30 19:57                   ` Maíra Canal
2026-10-02  8:12                     ` Thomas Zimmermann
2026-10-02 21:13                       ` Maíra Canal
2026-10-06  6:50                         ` Thomas Zimmermann

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20260923160049.1741651-1-holofermes@gmail.com \
    --to=holofermes@gmail.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=javierm@redhat.com \
    --cc=tzimmermann@suse.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.