[PATCH] drm/vc4: Start console with 32 bpp / 24 depth

[Thomas Zimmermann]

Hi

Am 05.01.23 um 09:36 schrieb Maxime Ripard:
> Hi,
> 
> On Thu, Jan 05, 2023 at 09:07:34AM +0100, Thomas Zimmermann wrote:
>> Invoke the generic console emulation with a 32 bits per pixel. The
>> preferred color depth is 24, so the current value of 16 bpp is too
>> small. This results in the following error message
>>
>> vc4-drm gpu: [drm] bpp/depth value of 16/24 not supported
>> vc4-drm gpu: [drm] No compatible format found
>> ------------[ cut here ]------------
>> WARNING: CPU: 2 PID: 66 at drivers/gpu/drm/drm_atomic.c:1604 __drm_atomic_helper_set_config+0x2e8/0x314 [drm]
>>
>> The problem has been present for a long, but has only now surfaced
>> as commit 37c90d589dc0 ("drm/fb-helper: Fix single-probe color-format
>> selection") attempts to improve selection of the color format.
>>
>> See [1] for the initial bug report.
>>
>> Reported-by: Maíra Canal <mcanal at igalia.com>
>> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
>> Tested-by: Maíra Canal <mcanal at igalia.com>
>> Fixes: 37c90d589dc0 ("drm/fb-helper: Fix single-probe color-format selection")
>> Cc: Thomas Zimmermann <tzimmermann at suse.de>
>> Cc: Javier Martinez Canillas <javierm at redhat.com>
>> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
>> Cc: Maxime Ripard <mripard at kernel.org>
>> Link: https://lore.kernel.org/dri-devel/20230102112927.26565-1-tzimmermann@suse.de/T/#mb09eb6f615f4b0302c78f250b4241ee48d1915f8 # 1
>> ---
>>   drivers/gpu/drm/vc4/vc4_drv.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
>> index 0ccaee57fe9a..64423b79982f 100644
>> --- a/drivers/gpu/drm/vc4/vc4_drv.c
>> +++ b/drivers/gpu/drm/vc4/vc4_drv.c
>> @@ -387,7 +387,7 @@ static int vc4_drm_bind(struct device *dev)
>>   	if (ret < 0)
>>   		goto unbind_all;
>>   
>> -	drm_fbdev_generic_setup(drm, 16);
>> +	drm_fbdev_generic_setup(drm, 32);
> 
> This is essentially a revert of f741b28fb299.
> 
> It's not clear to me what sets the depth preference to 24, because I'd
> rather change that.

I see. We should reduce the preferred color depth to 16 then. [1]

Best regards
Thomas

[1] 
https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/vc4/vc4_kms.c#L1048

> 
> Maxime

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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