[PATCH] platform/x86/intel/pmc: initialize empty PMT read result

[PATCH] platform/x86/intel/pmc: initialize empty PMT read result

[Yousef Alhouseen]

pmc_core_pmt_get_lpm_req() returns the last telemetry read status. When
firmware exposes no enabled low-power modes, the loop does not run
and the function returns an uninitialized stack value.

Initialize the status to success so an empty mode set is handled
deterministically.

Signed-off-by: Yousef Alhouseen <alhouseenyousef@gmail.com>
---
 drivers/platform/x86/intel/pmc/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
index 825ba5fa0bcb..9f77c0716e59 100644
--- a/drivers/platform/x86/intel/pmc/core.c
+++ b/drivers/platform/x86/intel/pmc/core.c
@@ -1583,7 +1583,7 @@ int pmc_core_pmt_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc, struct tel
 {
 	const u8 *lpm_indices;
 	int num_maps, mode_offset = 0;
-	int ret, lpm_size;
+	int ret = 0, lpm_size;
 	u8 mode;
 
 	lpm_indices = pmc->map->lpm_reg_index;
-- 
2.54.0

Re: [PATCH] platform/x86/intel/pmc: initialize empty PMT read result

[David Box]

On Tue, Jun 30, 2026 at 12:51:01PM +0200, Yousef Alhouseen wrote:
> pmc_core_pmt_get_lpm_req() returns the last telemetry read status. When
> firmware exposes no enabled low-power modes, the loop does not run
> and the function returns an uninitialized stack value.
> 
> Initialize the status to success so an empty mode set is handled
> deterministically.
> 
> Signed-off-by: Yousef Alhouseen <alhouseenyousef@gmail.com>
> ---
>  drivers/platform/x86/intel/pmc/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
> index 825ba5fa0bcb..9f77c0716e59 100644
> --- a/drivers/platform/x86/intel/pmc/core.c
> +++ b/drivers/platform/x86/intel/pmc/core.c
> @@ -1583,7 +1583,7 @@ int pmc_core_pmt_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc, struct tel
>  {
>  	const u8 *lpm_indices;
>  	int num_maps, mode_offset = 0;
> -	int ret, lpm_size;
> +	int ret = 0, lpm_size;
>  	u8 mode;
>  
>  	lpm_indices = pmc->map->lpm_reg_index;
> -- 
> 2.54.0
> 

Reviewed-by: David E. Box <david.e.box@linux.intel.com>

Thanks

Re: [PATCH] platform/x86/intel/pmc: initialize empty PMT read result

[Ilpo Järvinen]

On Tue, 30 Jun 2026 12:51:01 +0200, Yousef Alhouseen wrote:

> pmc_core_pmt_get_lpm_req() returns the last telemetry read status. When
> firmware exposes no enabled low-power modes, the loop does not run
> and the function returns an uninitialized stack value.
> 
> Initialize the status to success so an empty mode set is handled
> deterministically.
> 
> [...]

Thank you for your contribution, it has been applied to my local
review-ilpo-next branch. Note it will show up in the public
platform-drivers-x86/review-ilpo-next branch only once I've pushed my
local branch there, which might take a while.

FYI [if applicable to your patch], as per Linus' policy change, also
fixes are mostly routed through for-next unless the fix is for a
commit introduced in the most recent cycle or is clearly a regression
fix.

The list of commits applied:
[1/1] platform/x86/intel/pmc: initialize empty PMT read result
      commit: 408b87a481e3ab33cba00292e4c80a30ba97f995

--
 i.