[PATCH] Fix loading of module radeonfb on PowerMac

[Mathieu Malaterre]

Tomi,

On Wed, Nov 2, 2016 at 9:28 AM, Tomi Valkeinen <tomi.valkeinen at ti.com> wrote:
> On 08/10/16 15:09, Mathieu Malaterre wrote:
>> When the linux kernel is build with (typical kernel ship with Debian
>> installer):
>>
>> CONFIG_FB_OF=y
>> CONFIG_VT_HW_CONSOLE_BINDING=y
>> CONFIG_FB_RADEON=m
>>
>> The offb driver takes precedence over module radeonfb. It is then
>> impossible to load the module, error reported is:
>>
>> [   96.551486] radeonfb 0000:00:10.0: enabling device (0006 -> 0007)
>> [   96.551526] radeonfb 0000:00:10.0: BAR 0: can't reserve [mem 0x98000000-0x9fffffff pref]
>> [   96.551531] radeonfb (0000:00:10.0): cannot request region 0.
>> [   96.551545] radeonfb: probe of 0000:00:10.0 failed with error -16
>>
>> This patch reproduce the behavior of the module radeon, so as to make it
>> possible to load radeonfb when offb is first loaded.
>>
>> It should be noticed that `offb_destroy` is never called which explain the
>> need to skip error detection on the radeon side.
>
> Why is that? It sounds rather bad if two drivers claim the same resources.

This has been working great so far for `radeon.ko`, so I assumed I
could shamelessly copy the behavior over to `radeonfb.ko`.

The original reference I found was from Benjamin Herrenschmidt here:
https://lists.freedesktop.org/archives/dri-devel/2010-August/002907.html

I am of course willing to try something else, but I would need some guidance.

Thanks much.