mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Sidharth Saha <ssaha2000@gmail.com>
To: Matheus Alves de Almeida <matheus.aalmeida@inf.ufrgs.br>,
	Louis Chauvet <louis.chauvet@bootlin.com>,
	Haneen Mohammed <hamohammed.sa@gmail.com>,
	Simona Vetter <simona@ffwll.ch>,
	Melissa Wen <melissa.srw@gmail.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@gmail.com>,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/5] drm/vkms: make argb_u16_to_RGB565 round resulting values
Date: Sat, 7 Nov 2026 20:12:29 -0700	[thread overview]
Message-ID: <097af97e-4d8a-477e-8eae-89f3fe485dc1@gmail.com> (raw)
In-Reply-To: <20260928005301.367977-2-matheus.aalmeida@inf.ufrgs.br>

Hi Matheus,

I wrote a KUnit test for argb_u16_to_RGB565() covering zero and max
values, the channel midpoint (0x8000 -> 16/32/16), the 0->1 rounding
step for a 5-bit channel (1057 -> 0, 1058 -> 1), and distinct values
per channel to catch channel placement.

Without this patch, the midpoint, above-step and distinct cases fail
(e.g. green comes out 31 instead of 32, i.e. truncated). With it, all
six cases pass.

Tested-by: Sidharth Saha ssaha2000@gmail.com

Since this rounding fix was lost once before in a refactor, I'm happy
to send the test as a follow-up patch once this series lands, or you're
welcome to fold it into a v2 if that's easier.

Thanks,
Sidharth

On 9/27/2026 5:52 PM, Matheus Alves de Almeida wrote:
> Currently, argb_u16_to_RGB565() truncates the resulting channel values.


  reply	other threads:[~2026-11-08  3:12 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-28  0:52 [PATCH 0/5] drm/vkms: support more formats and fix RGB565 regression Matheus Alves de Almeida
2026-09-28  0:52 ` [PATCH 1/5] drm/vkms: make argb_u16_to_RGB565 round resulting values Matheus Alves de Almeida
2026-11-08  3:12   ` Sidharth Saha [this message]
2026-09-28  0:52 ` [PATCH 2/5] drm/vkms: support BGR565 writeback Matheus Alves de Almeida
2026-09-28  0:52 ` [PATCH 3/5] drm/vkms: add a helper for channel to argb_u16 conversion Matheus Alves de Almeida
2026-09-28  0:53 ` [PATCH 4/5] drm/vkms: add support for RGB332 Matheus Alves de Almeida
2026-09-28  0:53 ` [PATCH 5/5] drm/vkms: add support for BGR233 Matheus Alves de Almeida
2026-10-12 19:18 ` [PATCH 0/5] drm/vkms: support more formats and fix RGB565 regression Matheus Alves de Almeida
2026-11-08  3:08 ` Sidharth Saha

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=097af97e-4d8a-477e-8eae-89f3fe485dc1@gmail.com \
    --to=ssaha2000@gmail.com \
    --cc=airlied@gmail.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=hamohammed.sa@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=louis.chauvet@bootlin.com \
    --cc=maarten.lankhorst@linux.intel.com \
    --cc=matheus.aalmeida@inf.ufrgs.br \
    --cc=melissa.srw@gmail.com \
    --cc=mripard@kernel.org \
    --cc=simona@ffwll.ch \
    --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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®