[PATCH] drm/amdgpu: fix SI handling in amdgpu_device_asic_has_dc_support()

[Quan, Evan]

[AMD Official Use Only]

Reviewed-by: Evan Quan <evan.quan at amd.com>

> -----Original Message-----
> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Alex
> Deucher
> Sent: Thursday, November 4, 2021 11:26 AM
> To: amd-gfx at lists.freedesktop.org
> Cc: Deucher, Alexander <Alexander.Deucher at amd.com>
> Subject: [PATCH] drm/amdgpu: fix SI handling in
> amdgpu_device_asic_has_dc_support()
> 
> Properly handle SI DC support when CONFIG_DRM_AMD_DC_SI is not
> set.
> 
> Fixes: f7f12b25823c0d ("drm/amdgpu: default to true in
> amdgpu_device_asic_has_dc_support")
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 95fec36e385e..db3728a11481 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -3166,11 +3166,21 @@ bool
> amdgpu_device_asic_has_dc_support(enum amd_asic_type asic_type)
>  {
>  	switch (asic_type) {
>  #if defined(CONFIG_DRM_AMD_DC)
> -#if defined(CONFIG_DRM_AMD_DC_SI)
>  	case CHIP_TAHITI:
>  	case CHIP_PITCAIRN:
>  	case CHIP_VERDE:
>  	case CHIP_OLAND:
> +		/*
> +		 * 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.
> +		 */
> +#if defined(CONFIG_DRM_AMD_DC_SI)
> +		return amdgpu_dc > 0;
> +#else
> +		return false;
>  #endif
>  	case CHIP_BONAIRE:
>  	case CHIP_KAVERI:
> --
> 2.31.1