[PATCH] Revert "vgaarb: Keep adding VGA device in queue"

[Michel Dänzer]

On 2019-05-10 5:42 p.m., Daniel Vetter wrote:
> On Fri, May 10, 2019 at 09:29:58AM -0500, Alex Deucher wrote:
>> This breaks multiple graphics cards in the Amigaone x5000
>> on PPC.
>>
>> This reverts commit 3d42f1ddc47a69c0ce155f9f30d764c4d689a5fa.
>>
>> Bug: https://bugs.freedesktop.org/show_bug.cgi?id=109345
>> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
>> CC: Aaron Ma <aaron.ma at canonical.com>
> 
> Given that the bug is a bit a mess I think we need to add a bit more
> context here in the commit message. My understanding:
> 
> Goal of the revert commit was to make the integrated boot device the
> primary one, if we can't detect which one is the boot device, instead of
> the last one. Which makes some sense.
> 
> Now people have relied on the kernel picking the last one, which usually
> is an add-on card, and therefore simply plugging in an add-on card allows
> them to overwrite the default choice. Which also makes sense, and since
> it's the older behaviour, wins.
> 
> I think it'd be good to add a comment here that this behaviour has become
> uapi, e.g.
> 
> 	/* Add at the front so that we pick the last device as fallback
> 	 * default, with the usual result that plug in cards are preferred
> 	 * over integrated graphics. */
> 
> With that (or similar) and more commit message context:

The bug reporter's system doesn't have integrated graphics though, just
two plug-in cards. It's not clear to me yet that their expectation of
Xorg to pick any particular one of them without configuration was justified.


-- 
Earthling Michel Dänzer               |              https://www.amd.com
Libre software enthusiast             |             Mesa and X developer