[PATCH] drm/ast: Fix black screen when getting out of suspend

[Jocelyn Falempe]

On 22/06/2022 20:34, Lyude Paul wrote:
> Some small nitpicks:
> 
> On Wed, 2022-06-22 at 14:48 +0200, Jocelyn Falempe wrote:
>> With an AST2600, the screen is garbage when going out of suspend.
>> This is because color settings are lost, and not restored on resume.
>> Force the color settings on DPMS_ON, to make sure the settings are correct.
>>
>> I didn't write this code, it comes from the out-of-tree aspeed driver v1.13
>> https://www.aspeedtech.com/support_driver/
>>
>> Signed-off-by: Jocelyn Falempe <jfalempe at redhat.com>
>> Tested-by: Venkat Tadikonda <venkateswara.rao at intel.com>
> 
> Should have a Cc: to stable imho, `dim` can do this for you:
> 
> https://drm.pages.freedesktop.org/maintainer-tools/dim.html

Sure I will add cc to stable for the v2
> 
>> ---
>>   drivers/gpu/drm/ast/ast_mode.c | 13 +++++++++++++
>>   1 file changed, 13 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
>> index 3eb9afecd9d4..cdddcb5c4439 100644
>> --- a/drivers/gpu/drm/ast/ast_mode.c
>> +++ b/drivers/gpu/drm/ast/ast_mode.c
>> @@ -990,6 +990,9 @@ static void ast_crtc_dpms(struct drm_crtc *crtc, int
>> mode)
>>   {
>>          struct ast_private *ast = to_ast_private(crtc->dev);
>>          u8 ch = AST_DPMS_VSYNC_OFF | AST_DPMS_HSYNC_OFF;
>> +       struct ast_crtc_state *ast_state;
>> +       const struct drm_format_info *format;
>> +       struct ast_vbios_mode_info *vbios_mode_info;
>>   
>>          /* TODO: Maybe control display signal generation with
>>           *       Sync Enable (bit CR17.7).
>> @@ -1007,6 +1010,16 @@ static void ast_crtc_dpms(struct drm_crtc *crtc, int
>> mode)
>>                          ast_dp_set_on_off(crtc->dev, 1);
>>                  }
>>   
>> +               ast_state = to_ast_crtc_state(crtc->state);
>> +               format = ast_state->format;
>> +
>> +               if (format){
> 
> Should be a space between ')' and '{'.

looks like I forget to run checkpatch.pl on it before sending :(

I'll wait a bit for other comments, and sent a v2 with cc for stable.
> 
> With that fixed, this is: Reviewed-by: Lyude Paul <lyude at redhat.com>
> 
>> +                       vbios_mode_info = &ast_state->vbios_mode_info;
>> +
>> +                       ast_set_color_reg(ast, format);
>> +                       ast_set_vbios_color_reg(ast, format,
>> vbios_mode_info);
>> +               }
>> +
>>                  ast_crtc_load_lut(ast, crtc);
>>                  break;
>>          case DRM_MODE_DPMS_STANDBY:
>