On 2024-08-27 15:53, sunpeng.li@xxxxxxx wrote:
> From: Leo Li <sunpeng.li@xxxxxxx>
>
> [Why]
>
> DCN IPS interoperates with other system idle power features, such as
> Zstates.
>
> On DCN35, there is a known issue where system Z8 + DCN IPS2 causes a
> hard hang. We observe this on systems where the SBIOS allows Z8.
>
> Though there is a SBIOS fix, there's no guarantee that users will get it
> any time soon, or even install it. A workaround is needed to prevent
> this from rearing its head in the wild.
>
> [How]
>
> For DCN35, check the pmfw version to determine whether the SBIOS has the
> fix. If not, set IPS1+RCG as the deepest possible state in all cases
> except for s0ix and display off (DPMS). Otherwise, enable all IPS
>
> Signed-off-by: Leo Li <sunpeng.li@xxxxxxx>
Reviewed-by: Harry Wentland <harry.wentland@xxxxxxx>
Harry
> ---
> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 26 ++++++++++++++++++-
> 1 file changed, 25 insertions(+), 1 deletion(-)
>
> 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 a18ecf8607232..a2e4973a4f6e3 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -1754,6 +1754,30 @@ static struct dml2_soc_bb *dm_dmub_get_vbios_bounding_box(struct amdgpu_device *
> return bb;
> }
>
> +static enum dmub_ips_disable_type dm_get_default_ips_mode(
> + struct amdgpu_device *adev)
> +{
> + /*
> + * On DCN35 systems with Z8 enabled, it's possible for IPS2 + Z8 to
> + * cause a hard hang. A fix exists for newer PMFW.
> + *
> + * As a workaround, for non-fixed PMFW, force IPS1+RCG as the deepest
> + * IPS state in all cases, except for s0ix and all displays off (DPMS),
> + * where IPS2 is allowed.
> + *
> + * When checking pmfw version, use the major and minor only.
> + */
> + if (amdgpu_ip_version(adev, DCE_HWIP, 0) == IP_VERSION(3, 5, 0) &&
> + (adev->pm.fw_version & 0x00FFFF00) < 0x005D6300)
> + return DMUB_IPS_RCG_IN_ACTIVE_IPS2_IN_OFF;
> +
> + if (amdgpu_ip_version(adev, DCE_HWIP, 0) >= IP_VERSION(3, 5, 0))
> + return DMUB_IPS_ENABLE;
> +
> + /* ASICs older than DCN35 do not have IPSs */
> + return DMUB_IPS_DISABLE_ALL;
> +}
> +
> static int amdgpu_dm_init(struct amdgpu_device *adev)
> {
> struct dc_init_data init_data;
> @@ -1871,7 +1895,7 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
> else if (amdgpu_dc_debug_mask & DC_FORCE_IPS_ENABLE)
> init_data.flags.disable_ips = DMUB_IPS_ENABLE;
> else
> - init_data.flags.disable_ips = DMUB_IPS_ENABLE;
> + init_data.flags.disable_ips = dm_get_default_ips_mode(adev);
>
> init_data.flags.disable_ips_in_vpb = 0;
>
