Re: [PATCH] platform/x86/amd/pmc: Fix S2D message ID on Rembrandt

[Mario Limonciello <superm1@kernel.org>]

On 11/1/26 23:35, Christian Aurich Zanettini Martins wrote:
> Commit 382fe403dc31 ("platform/x86/amd/pmc: Add STB support for AMD
> Desktop variants") added S2D message ID 0x9B for Granite Ridge (family
> 1Ah, model 44h), but only checks the model. Rembrandt is family 19h,
> model 44h and goes through the same AMD_CPU_ID_YC case, so it sends 0x9B
> instead of 0xBE. The firmware then reports a telemetry size of 1 instead
> of 0x100000 and amd_stb_s2d_init() fails with -EIO.
> 
> amd_stb_update_args() already checks for Zen 5 before using the Granite
> Ridge registers. Do the same for the message ID.
> 
> Fixes: 382fe403dc31 ("platform/x86/amd/pmc: Add STB support for AMD Desktop variants")
> Cc: stable@vger.kernel.org
> Signed-off-by: Christian Aurich Zanettini Martins <christian.aurichzm@gmail.com>
> ---
> 
> Notes:
>      Tested on a Lenovo IdeaPad Slim 3 15ARP10 (Ryzen 7 7735HS), with this
>      driver built out of tree for a 7.0 kernel. The size query returns 1 with
>      0x9B and 0x100000 with 0xBE. This laptop's firmware then reports S2D
>      address 0, so init still ends in -ENXIO here and I couldn't test an
>      actual STB dump.
>      
>      Based on v7.4-rc1. Found in my own boot logs.
> 
>   drivers/platform/x86/amd/pmc/mp1_stb.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/amd/pmc/mp1_stb.c b/drivers/platform/x86/amd/pmc/mp1_stb.c
> index 8a33e75b71c3..af9ecec532f0 100644
> --- a/drivers/platform/x86/amd/pmc/mp1_stb.c
> +++ b/drivers/platform/x86/amd/pmc/mp1_stb.c
> @@ -266,7 +266,7 @@ static bool amd_is_stb_supported(struct amd_pmc_dev *dev)
>   	switch (dev->cpu_id) {
>   	case AMD_CPU_ID_YC:
>   	case AMD_CPU_ID_CB:
> -		if (boot_cpu_data.x86_model == 0x44)
> +		if (cpu_feature_enabled(X86_FEATURE_ZEN5) && boot_cpu_data.x86_model == 0x44)
>   			dev->stb_arg.s2d_msg_id = 0x9B;
>   		else
>   			dev->stb_arg.s2d_msg_id = 0xBE;

Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>