Re: [PATCH] platform/x86/intel/pmc: Disable C1 auto-demotion during suspend

Mario Limonciello
2024-10-02T03:11:46Z

On 10/1/2024 17:58, David E. Box wrote:
> On some platforms, aggressive C1 auto-demotion may lead to failure to enter
> the deepest C-state during suspend-to-idle, causing high power consumption.
> To prevent this, disable C1 auto-demotion during suspend and re-enable on
> resume.
>
> Signed-off-by: David E. Box <david.e.box@linux.intel.com>
> ---
> drivers/platform/x86/intel/pmc/arl.c | 3 +--
> drivers/platform/x86/intel/pmc/cnp.c | 28 +++++++++++++++++++++++++++-
> drivers/platform/x86/intel/pmc/lnl.c | 3 +--
> drivers/platform/x86/intel/pmc/mtl.c | 3 +--
> 4 files changed, 30 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/platform/x86/intel/pmc/arl.c b/drivers/platform/x86/intel/pmc/arl.c
> index e10527c4e3e0..05dec4f5019f 100644
> --- a/drivers/platform/x86/intel/pmc/arl.c
> +++ b/drivers/platform/x86/intel/pmc/arl.c
> @@ -687,9 +687,8 @@ static void arl_d3_fixup(void)
> static int arl_resume(struct pmc_dev *pmcdev)
> {
> arl_d3_fixup();
> - pmc_core_send_ltr_ignore(pmcdev, 3, 0);
>
> - return pmc_core_resume_common(pmcdev);
> + return cnl_resume(pmcdev);
> }
>
> int arl_core_init(struct pmc_dev *pmcdev)
> diff --git a/drivers/platform/x86/intel/pmc/cnp.c b/drivers/platform/x86/intel/pmc/cnp.c
> index 513c02670c5a..5b8b3ac7f061 100644
> --- a/drivers/platform/x86/intel/pmc/cnp.c
> +++ b/drivers/platform/x86/intel/pmc/cnp.c
> @@ -7,7 +7,8 @@
> * All Rights Reserved.
> *
> */
> -
> +#define DEBUG

Did you mean to pull this out before submitting?

> +#include <linux/suspend.h>
> #include "core.h"
>
> /* Cannon Lake: PGD PFET Enable Ack Status Register(s) bitmap */
> @@ -206,8 +207,24 @@ const struct pmc_reg_map cnp_reg_map = {
> .etr3_offset = ETR3_OFFSET,
> };
>
> +
> +static DEFINE_PER_CPU(u64, pkg_cst_config);
> +
> void cnl_suspend(struct pmc_dev *pmcdev)
> {
> + if (!pm_suspend_via_firmware()) {
> + u64 val;
> + int cpunum;
> +
> + for_each_online_cpu(cpunum) {
> + rdmsrl_on_cpu(cpunum, MSR_PKG_CST_CONFIG_CONTROL, &val);
> + per_cpu(pkg_cst_config, cpunum) = val;
> + val &= ~NHM_C1_AUTO_DEMOTE;
> + wrmsrl_on_cpu(cpunum, MSR_PKG_CST_CONFIG_CONTROL, val);
> + pr_debug("%s: cpu:%d cst %llx\n", __func__, cpunum, val);
> + }
> + }
> +
> /*
> * Due to a hardware limitation, the GBE LTR blocks PC10
> * when a cable is attached. To unblock PC10 during suspend,
> @@ -220,6 +237,15 @@ int cnl_resume(struct pmc_dev *pmcdev)
> {
> pmc_core_send_ltr_ignore(pmcdev, 3, 0);
>
> + if (!pm_suspend_via_firmware()) {
> + int cpunum;
> +
> + for_each_online_cpu(cpunum) {
> + pr_debug("%s: cpu:%d cst %llx\n", __func__, cpunum, per_cpu(pkg_cst_config, cpunum));
> + wrmsrl_on_cpu(cpunum, MSR_PKG_CST_CONFIG_CONTROL, per_cpu(pkg_cst_config, cpunum));
> + }
> + }
> +
> return pmc_core_resume_common(pmcdev);
> }
>
> diff --git a/drivers/platform/x86/intel/pmc/lnl.c b/drivers/platform/x86/intel/pmc/lnl.c
> index e7a8077d1a3e..be029f12cdf4 100644
> --- a/drivers/platform/x86/intel/pmc/lnl.c
> +++ b/drivers/platform/x86/intel/pmc/lnl.c
> @@ -546,9 +546,8 @@ static void lnl_d3_fixup(void)
> static int lnl_resume(struct pmc_dev *pmcdev)
> {
> lnl_d3_fixup();
> - pmc_core_send_ltr_ignore(pmcdev, 3, 0);
>
> - return pmc_core_resume_common(pmcdev);
> + return cnl_resume(pmcdev);
> }
>
> int lnl_core_init(struct pmc_dev *pmcdev)
> diff --git a/drivers/platform/x86/intel/pmc/mtl.c b/drivers/platform/x86/intel/pmc/mtl.c
> index 91f2fa728f5c..fc6a89b8979f 100644
> --- a/drivers/platform/x86/intel/pmc/mtl.c
> +++ b/drivers/platform/x86/intel/pmc/mtl.c
> @@ -988,9 +988,8 @@ static void mtl_d3_fixup(void)
> static int mtl_resume(struct pmc_dev *pmcdev)
> {
> mtl_d3_fixup();
> - pmc_core_send_ltr_ignore(pmcdev, 3, 0);
>
> - return pmc_core_resume_common(pmcdev);
> + return cnl_resume(pmcdev);
> }
>
> int mtl_core_init(struct pmc_dev *pmcdev)