linux-kernel - Re: [PATCH 3/5] drm: ssd130x: Fix rectangle updates

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Date:   Tue, 15 Mar 2022 13:28:27 +0100
From:   Javier Martinez Canillas <javierm@...hat.com>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Noralf Trønnes <noralf@...nnes.org>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/5] drm: ssd130x: Fix rectangle updates

On 3/15/22 12:07, Geert Uytterhoeven wrote:
> The rectangle update functions ssd130x_fb_blit_rect() and
> ssd130x_update_rect() do not behave correctly when x1 != 0 or y1 !=
> 0, or when y1 or y2 are not aligned to display page boundaries.
> E.g. when used as a text console, only the first line of text is shown
> on the display.
> 
>   1. The buffer passed by ssd130x_fb_blit_rect() points to the first
>      byte of monochrome bitmap data, and thus has its origin at (x1,
>      y1), while ssd130x_update_rect() assumes it is at (0, 0).
>      Fix ssd130x_update_rect() by changing the vertical and horizontal
>      loop ranges, and adding the offsets only when needed.
> 
>   2. In ssd130x_fb_blit_rect(), align y1 and y2 to the display page
>      boundaries before doing the color conversion, so the full page
>      is converted and updated.
>      Remove the correction for an unaligned y1 from
>      ssd130x_update_rect(), and add a check to make sure y1 is aligned.
> 
> Fixes: a61732e808672cfa ("drm: Add driver for Solomon SSD130x OLED displays")
> Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
> ---

Thanks for fixing this too.

Acked-by: Javier Martinez Canillas <javierm@...hat.com>

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat