Message-ID: <6a3d0907-5e04-5e72-cf45-3eb619ea6efb@riseup.net>
Date:   Thu, 9 Mar 2023 14:51:58 -0300
MIME-Version: 1.0
Subject: Re: [PATCH v2] drm/format-helper: Make conversion_buf_size() support
 sub-byte pixel fmts
Content-Language: en-US
To:     Javier Martinez Canillas <javierm@redhat.com>,
        linux-kernel@vger.kernel.org
Cc:     =?UTF-8?Q?Ma=c3=adra_Canal?= <mairacanal@riseup.net>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Maxime Ripard <maxime@cerno.tech>,
        Daniel Vetter <daniel@ffwll.ch>,
        David Airlie <airlied@gmail.com>,
        David Gow <davidgow@google.com>,
        =?UTF-8?B?Sm9zw6kgRXhww7NzaXRv?= <jose.exposito89@gmail.com>,
        dri-devel@lists.freedesktop.org
References: <20230307215039.346863-1-javierm@redhat.com>
From:   Arthur Grillo Queiroz Cabral <arthurgrillo@riseup.net>
In-Reply-To: <20230307215039.346863-1-javierm@redhat.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk


Hi,

On 07/03/23 18:50, Javier Martinez Canillas wrote:
> There are DRM fourcc formats that have pixels smaller than a byte, but the
> conversion_buf_size() function assumes that pixels are a multiple of bytes
> and use the struct drm_format_info .cpp field to calculate the dst_pitch.
> 
> Instead, calculate it by using the bits per pixel (bpp) and divide it by 8
> to account for formats that have sub-byte pixels.
> 
> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
> ---
> Tested by making sure that the following command still succeeds:
> 
> ./tools/testing/kunit/kunit.py run \
> --kunitconfig=drivers/gpu/drm/tests/.kunitconfig
> 
> Changes in v2:
> - Drop an unused variable, that was pointed out by the kernel robot.
> 
>  drivers/gpu/drm/tests/drm_format_helper_test.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/tests/drm_format_helper_test.c b/drivers/gpu/drm/tests/drm_format_helper_test.c
> index 9536829c6e3a..84b5cc29c8fc 100644
> --- a/drivers/gpu/drm/tests/drm_format_helper_test.c
> +++ b/drivers/gpu/drm/tests/drm_format_helper_test.c
> @@ -409,12 +409,15 @@ static size_t conversion_buf_size(u32 dst_format, unsigned int dst_pitch,
>  				  const struct drm_rect *clip)
>  {
>  	const struct drm_format_info *dst_fi = drm_format_info(dst_format);
> +	unsigned int bpp;
>  
>  	if (!dst_fi)
>  		return -EINVAL;
>  
> -	if (!dst_pitch)
> -		dst_pitch = drm_rect_width(clip) * dst_fi->cpp[0];
> +	if (!dst_pitch) {
> +		bpp = drm_format_info_bpp(dst_fi, 0);
> +		dst_pitch = DIV_ROUND_UP(drm_rect_width(clip) * bpp, 8);
> +	}
>  
>  	return dst_pitch * drm_rect_height(clip);
>  }

Ran it on UML, arm and powerpc with my patch above it, All looks good
:).

Reviewed-by: Arthur Grillo <arthurgrillo@riseup.net>

Thanks,
Grillo