linux-kernel - Re: [PATCH 00/17] fbdev: Remove FBINFO_DEFAULT and FBINFO_FLAG

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Message-ID: <b8d28b32-62ff-93fd-ad24-990f82efa38a@suse.de>
Date:   Wed, 12 Jul 2023 08:44:40 +0200
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     Sam Ravnborg <sam@...nborg.org>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-hyperv@...r.kernel.org,
        kvm@...r.kernel.org, linux-sh@...r.kernel.org, deller@....de,
        linux-staging@...ts.linux.dev, javierm@...hat.com,
        amd-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, linux-fbdev@...r.kernel.org,
        linux-input@...r.kernel.org, linux-nvidia@...ts.surfsouth.com,
        linux-omap@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-geode@...ts.infradead.org, linux-media@...r.kernel.org
Subject: Re: [PATCH 00/17] fbdev: Remove FBINFO_DEFAULT and
 FBINFO_FLAG_DEFAULT flags



Am 11.07.23 um 16:47 schrieb Sam Ravnborg:
> Hi Thomas,
> 
> On Tue, Jul 11, 2023 at 08:24:40AM +0200, Thomas Zimmermann wrote:
>> Hi Sam
>>
>> Am 10.07.23 um 19:19 schrieb Sam Ravnborg:
>>> Hi Thomas,
>>>
>>> On Mon, Jul 10, 2023 at 02:50:04PM +0200, Thomas Zimmermann wrote:
>>>> Remove the unused flags FBINFO_DEFAULT and FBINFO_FLAG_DEFAULT from
>>>> fbdev and drivers, as briefly discussed at [1]. Both flags were maybe
>>>> useful when fbdev had special handling for driver modules. With
>>>> commit 376b3ff54c9a ("fbdev: Nuke FBINFO_MODULE"), they are both 0
>>>> and have no further effect.
>>>>
>>>> Patches 1 to 7 remove FBINFO_DEFAULT from drivers. Patches 2 to 5
>>>> split this by the way the fb_info struct is being allocated. All flags
>>>> are cleared to zero during the allocation.
>>>>
>>>> Patches 8 to 16 do the same for FBINFO_FLAG_DEFAULT. Patch 8 fixes
>>>> an actual bug in how arch/sh uses the tokne for struct fb_videomode,
>>>> which is unrelated.
>>>>
>>>> Patch 17 removes both flag constants from <linux/fb.h>
>>>
>>> We have a few more flags that are unused - should they be nuked too?
>>> FBINFO_HWACCEL_FILLRECT
>>> FBINFO_HWACCEL_ROTATE
>>> FBINFO_HWACCEL_XPAN
>>
>> It seems those are there for completeness. Nothing sets _ROTATE, the others
>> are simply never checked. According to the comments, some are required, some
>> are optional. I don't know what that means.
>>
>> IIRC there were complains about performance when Daniel tried to remove
>> fbcon acceleration, so not all _HWACCEL_ flags are unneeded.
>>
>> Leaving them in for reference/completeness might be an option; or not. I
>> have no strong feelings about those flags.
>>
>>>
>>> Unused as in no references from fbdev/core/*
>>>
>>> I would rather see one series nuke all unused FBINFO flags in one go.
>>> Assuming my quick grep are right and the above can be dropped.
>>
>> I would not want to extend this series. I'm removing _DEFAULT as it's
>> absolutely pointless and confusing.
> 
> OK, makes sense and thanks for the explanation.
> 
> The series is:
> Acked-by: Sam Ravnborg <sam@...nborg.org>

Thanks a lot.

> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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