[PATCH 1/3] drm/amd/display: Add DC Debug mask to disable features for bringup

[Kazlauskas, Nicholas]

On 2020-05-12 12:45 p.m., Harry Wentland wrote:
> [Why]
> At bringup we want to be able to disable various power features.
> 
> [How]
> These features are already exposed as dc_debug_options and exercised
> on other OSes. Create a new dc_debug_mask module parameter and expose
> relevant bits, in particular
>   * DC_DISABLE_PIPE_SPLIT
>   * DC_DISABLE_STUTTER
>   * DC_DISABLE_DSC
>   * DC_DISABLE_CLOCK_GATING
> 
> Signed-off-by: Harry Wentland <harry.wentland at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu.h               |  1 +
>   drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c           |  8 ++++++++
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 14 ++++++++++++++
>   drivers/gpu/drm/amd/include/amd_shared.h          |  7 +++++++
>   4 files changed, 30 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index 2a806cb55b78..13c8ccdb2948 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -173,6 +173,7 @@ extern int amdgpu_gpu_recovery;
>   extern int amdgpu_emu_mode;
>   extern uint amdgpu_smu_memory_pool_size;
>   extern uint amdgpu_dc_feature_mask;
> +extern uint amdgpu_dc_debug_mask;
>   extern uint amdgpu_dm_abm_level;
>   extern struct amdgpu_mgpu_info mgpu_info;
>   extern int amdgpu_ras_enable;
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index 589000938ab6..76707491657e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -140,6 +140,7 @@ int amdgpu_emu_mode = 0;
>   uint amdgpu_smu_memory_pool_size = 0;
>   /* FBC (bit 0) disabled by default*/
>   uint amdgpu_dc_feature_mask = 0;
> +uint amdgpu_dc_debug_mask = 0;
>   int amdgpu_async_gfx_ring = 1;
>   int amdgpu_mcbp = 0;
>   int amdgpu_discovery = -1;
> @@ -714,6 +715,13 @@ MODULE_PARM_DESC(queue_preemption_timeout_ms, "queue preemption timeout in ms (1
>   MODULE_PARM_DESC(dcfeaturemask, "all stable DC features enabled (default))");
>   module_param_named(dcfeaturemask, amdgpu_dc_feature_mask, uint, 0444);
>   
> +/**
> + * DOC: dcdebugmask (uint)
> + * Override display features enabled. See enum DC_DEBUG_MASK in drivers/gpu/drm/amd/include/amd_shared.h.
> + */
> +MODULE_PARM_DESC(dcdebugmask, "all debug options disabled (default))");
> +module_param_named(dcdebugmask, amdgpu_dc_debug_mask, uint, 0444);
> +
>   /**
>    * DOC: abmlevel (uint)
>    * Override the default ABM (Adaptive Backlight Management) level used for DC
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 60fe64aef11b..bf347ca43064 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -918,6 +918,20 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
>   		goto error;
>   	}
>   
> +	if (amdgpu_dc_debug_mask & DC_DISABLE_PIPE_SPLIT) {
> +		adev->dm.dc->debug.force_single_disp_pipe_split = false;
> +		adev->dm.dc->debug.pipe_split_policy = MPC_SPLIT_AVOID;
> +	}
> +
> +	if (amdgpu_dc_debug_mask & DC_DISABLE_STUTTER)
> +		adev->dm.dc->debug.disable_stutter = true;
> +
> +	if (amdgpu_dc_debug_mask & DC_DISABLE_DSC)
> +		adev->dm.dc->debug.disable_dsc = true;
> +
> +	if (amdgpu_dc_debug_mask & DC_DISABLE_CLOCK_GATING)
> +		adev->dm.dc->debug.disable_clock_gate = true;
> +

Series is Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>

Note that we fill in device defaults during dc_create, but there are 
some debug options which we unfortunately do reference during 
dc_create() itself which would apply some options too late in the sequence.

Fortunately, I don't think that's the case for any of these debug 
options, but it's something to keep in mind at least. That's what the 
init_flags were added for I think, and those generally have preference 
over debug option overrides when available (from my understanding).

Regards,
Nicholas Kazlauskas

>   	r = dm_dmub_hw_init(adev);
>   	if (r) {
>   		DRM_ERROR("DMUB interface failed to initialize: status=%d\n", r);
> diff --git a/drivers/gpu/drm/amd/include/amd_shared.h b/drivers/gpu/drm/amd/include/amd_shared.h
> index d655a76bedc6..92126c54cb1c 100644
> --- a/drivers/gpu/drm/amd/include/amd_shared.h
> +++ b/drivers/gpu/drm/amd/include/amd_shared.h
> @@ -150,6 +150,13 @@ enum DC_FEATURE_MASK {
>   	DC_PSR_MASK = 0x8,
>   };
>   
> +enum DC_DEBUG_MASK {
> +	DC_DISABLE_PIPE_SPLIT = 0x1,
> +	DC_DISABLE_STUTTER = 0x2,
> +	DC_DISABLE_DSC = 0x4,
> +	DC_DISABLE_CLOCK_GATING = 0x8
> +};
> +
>   enum amd_dpm_forced_level;
>   /**
>    * struct amd_ip_funcs - general hooks for managing amdgpu IP Blocks
>