Re: [PATCH 2/2] drm/amdgpu: Disable PCIE_DPM on Intel RKL Platform

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 25 Aug 2021, Koba Ko <koba.ko@canonical.com> wrote:
> AMD polaris GPUs have an issue about audio noise on RKL platform,
> they provide a commit to fix but for SMU7-based GPU still
> need another module parameter,
>
> For avoiding the module parameter, switch PCI_DPM by determining
> intel platform in amd drm driver.

I'll just note that you could have a Tiger Lake PCH combined with a
number of platforms other than Rocket Lake, including not just the
obvious Tiger Lake but also Sky Lake, Kaby Lake, Coffee Lake, and Comet
Lake.

Again, I don't know what the root cause or fix should be, the workaround
presented here impacts a much larger number of platforms than where
you're claiming the issue is.

BR,
Jani.


>
> Fixes: 1a31474cdb48 ("drm/amd/pm: workaround for audio noise issue")
> Ref: https://lists.freedesktop.org/archives/amd-gfx/2021-August/067413.html
> Signed-off-by: Koba Ko <koba.ko@canonical.com>
> ---
>  .../drm/amd/pm/powerplay/hwmgr/smu7_hwmgr.c   | 21 ++++++++++++++++++-
>  1 file changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_hwmgr.c b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_hwmgr.c
> index 0541bfc81c1b..346110dd0f51 100644
> --- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_hwmgr.c
> +++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_hwmgr.c
> @@ -1733,6 +1733,25 @@ static int smu7_disable_dpm_tasks(struct pp_hwmgr *hwmgr)
>  	return result;
>  }
>  
> +#include <drm/intel_pch.h>
> +
> +static bool intel_tgp_chk(void)
> +{
> +	struct pci_dev *pch = NULL;
> +	unsigned short id;
> +
> +	while ((pch = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, pch))) {
> +		if (pch->vendor != PCI_VENDOR_ID_INTEL)
> +			continue;
> +
> +		id = pch->device & INTEL_PCH_DEVICE_ID_MASK;
> +		if (id == INTEL_PCH_TGP_DEVICE_ID_TYPE || INTEL_PCH_TGP2_DEVICE_ID_TYPE)

PS. This is always true. ;)

> +			return true;
> +	}
> +
> +	return false;
> +}
> +
>  static void smu7_init_dpm_defaults(struct pp_hwmgr *hwmgr)
>  {
>  	struct smu7_hwmgr *data = (struct smu7_hwmgr *)(hwmgr->backend);
> @@ -1758,7 +1777,7 @@ static void smu7_init_dpm_defaults(struct pp_hwmgr *hwmgr)
>  
>  	data->mclk_dpm_key_disabled = hwmgr->feature_mask & PP_MCLK_DPM_MASK ? false : true;
>  	data->sclk_dpm_key_disabled = hwmgr->feature_mask & PP_SCLK_DPM_MASK ? false : true;
> -	data->pcie_dpm_key_disabled = hwmgr->feature_mask & PP_PCIE_DPM_MASK ? false : true;
> +	data->pcie_dpm_key_disabled = intel_tgp_chk() || !(hwmgr->feature_mask & PP_PCIE_DPM_MASK);
>  	/* need to set voltage control types before EVV patching */
>  	data->voltage_control = SMU7_VOLTAGE_CONTROL_NONE;
>  	data->vddci_control = SMU7_VOLTAGE_CONTROL_NONE;

-- 
Jani Nikula, Intel Open Source Graphics Center