[PATCH v2] drm/amdgpu: Don't default to DC support for Kaveri and older

[Harry Wentland]

On 2018-05-08 11:28 AM, Deucher, Alexander wrote:
> You need to include mullins as well.  It's the same feature set as kabini.
> 

Good catch. v3 incoming.

> 
> Alex
> 
> 
> 
> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> *From:* amd-gfx <amd-gfx-bounces at lists.freedesktop.org> on behalf of Harry Wentland <harry.wentland at amd.com>
> *Sent:* Monday, May 7, 2018 7:24 PM
> *To:* amd-gfx at lists.freedesktop.org; Deucher, Alexander
> *Cc:* Wentland, Harry
> *Subject:* [PATCH v2] drm/amdgpu: Don't default to DC support for Kaveri and older
>  
> We've had a number of users report failures to detect and light up
> display with DC with LVDS and VGA. These connector types are not
> currently supported with DC. I'd like to add support but unfortunately
> don't have a system with LVDS or VGA available.
> 
> In order not to cause regressions we should probably fallback to the
> non-DC driver for ASICs that support VGA and LVDS.
> 
> These ASICs are:
>  * Bonaire
>  * Kabini
>  * Kaveri
> 
> ASIC support can always be force enabled with amdgpu.dc=1
> 
> v2: Keep Hawaii on DC
> 
> Signed-off-by: Harry Wentland <harry.wentland at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 887f7c9e84e0..0a23134147b7 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -2141,9 +2141,17 @@ bool amdgpu_device_asic_has_dc_support(enum amd_asic_type asic_type)
>          switch (asic_type) {
>  #if defined(CONFIG_DRM_AMD_DC)
>          case CHIP_BONAIRE:
> -       case CHIP_HAWAII:
>          case CHIP_KAVERI:
>          case CHIP_KABINI:
> +               /*
> +                * We have systems in the wild with these ASICs that require
> +                * LVDS and VGA support which is not supported with DC.
> +                *
> +                * Fallback to the non-DC driver here by default so as not to
> +                * cause regressions.
> +                */
> +               return amdgpu_dc > 0;
> +       case CHIP_HAWAII:
>          case CHIP_MULLINS:
>          case CHIP_CARRIZO:
>          case CHIP_STONEY:
> -- 
> 2.17.0
> 
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