linux-kernel - Re: [PATCH 2/8] drm/fb-helper: Add support for DRM_FORMAT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Yg6xXFouzq/4YCgU@ravnborg.org>
Date:   Thu, 17 Feb 2022 21:34:36 +0100
From:   Sam Ravnborg <sam@...nborg.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Thomas Zimmermann <tzimmermann@...e.de>,
        Linux Fbdev development list <linux-fbdev@...r.kernel.org>,
        David Airlie <airlied@...ux.ie>, Helge Deller <deller@....de>,
        Javier Martinez Canillas <javierm@...hat.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux/m68k <linux-m68k@...r.kernel.org>,
        DRI Development <dri-devel@...ts.freedesktop.org>
Subject: Re: [PATCH 2/8] drm/fb-helper: Add support for DRM_FORMAT_C[124]

Hi Geert,

> > > +     switch (fb->format->depth) {
> >
> > The depth field is deprecated. It's probably better to use
> > fb->format->format and test against 4CC codes.
> 
> The reason I checked for depth instead of a 4CC code is that the only
> thing that matters here is the number of bits per pixel.  Hence this
> function won't need any changes to support R1, R2, R4, and D1 later.
> When we get here, we already know that we are using a format that
> is supported by the fbdev helper code, and thus passed the 4CC
> checks elsewhere.
> 
> Alternatively, we could introduce drm_format_info_bpp() earlier in
> the series, and use that?

The drm_format_info_bpp() is very descriptive, so yes it would be good to use
it here also.

	Sam