[PATCH] drm/mgag200: Fix gamma lut not initialized.

[Thomas Zimmermann]

Hi

Am 10.05.23 um 11:29 schrieb Jocelyn Falempe:
> On 10/05/2023 11:15, Thomas Zimmermann wrote:
>> Hi,
>>
>> oh great! Thank you for fixing this bug. And sorry that I broke it.
>>
>> Am 10.05.23 um 10:54 schrieb Jocelyn Falempe:
>>> When mgag200 switched from simple KMS to regular atomic helpers,
>>> the initialization of the gamma settings was lost.
>>> This leads to a black screen, if the bios/uefi doesn't use the same
>>> pixel color depth.
>>>
>>> Link: https://bugzilla.redhat.com/show_bug.cgi?id=2171155
>>> Fixes: 1baf9127c482 ("drm/mgag200: Replace simple-KMS with regular 
>>> atomic helpers")
>>> Tested-by: Phil Oester <kernel at linuxace.com>
>>> Signed-off-by: Jocelyn Falempe <jfalempe at redhat.com>
>>
>> Also needs:
>>
>> Cc: <stable at vger.kernel.org> # v6.1+
> 
> Should I send a v2 with this added ?

Yes, please.

>>
>> In terms of what it does:
>>
>> Reviewed-by: Thomas Zimmermann <tzimmermann at suse.de>
>>
>> but the patch is apparently for against an old version. (v6.1?) The 
>> code in mgag200_crtc_helper_atomic_enable has changed quite a bit.
> 
> Yes, I based it on the culprit commit 1baf9127c482, but it applies 
> cleanly with git am -3 on top of v6.3

Rather send a patch against drm-misc-fixes and let backporters sort it 
out. That's current practice AFAIK. You could also reply to your v2 
patch mail with a link to the v1 patch.

Best regards
Thomas

> 
>>
>> Best regards
>> Thomas
>>
>>> ---
>>>   drivers/gpu/drm/mgag200/mgag200_mode.c | 5 +++++
>>>   1 file changed, 5 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c 
>>> b/drivers/gpu/drm/mgag200/mgag200_mode.c
>>> index 461da1409fdf..911d46741e40 100644
>>> --- a/drivers/gpu/drm/mgag200/mgag200_mode.c
>>> +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
>>> @@ -819,6 +819,11 @@ static void 
>>> mgag200_crtc_helper_atomic_enable(struct drm_crtc *crtc,
>>>       else if (mdev->type == G200_EV)
>>>           mgag200_g200ev_set_hiprilvl(mdev);
>>> +    if (crtc_state->gamma_lut)
>>> +        mgag200_crtc_set_gamma(mdev, format, 
>>> crtc_state->gamma_lut->data);
>>> +    else
>>> +        mgag200_crtc_set_gamma_linear(mdev, format);
>>> +
>>>       mgag200_enable_display(mdev);
>>>       if (mdev->type == G200_WB || mdev->type == G200_EW3)
>>>
>>> base-commit: 1baf9127c482a3a58aef81d92ae751798e2db202
>>
> 

-- 
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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