Hi,
On 2/23/22 18:52, Mario Limonciello wrote:
> commit 59348401ebed ("platform/x86: amd-pmc: Add special handling for
> timer based S0i3 wakeup") adds support for using another platform timer
> in lieu of the RTC which doesn't work properly on some systems. This path
> was validated and worked well before submission. During the 5.16-rc1 merge
> window other patches were merged that caused this to stop working properly.
>
> When this feature was used with 5.16-rc1 or later some OEM laptops with the
> matching firmware requirements from that commit would shutdown instead of
> program a timer based wakeup.
>
> This was bisected to commit 8d89835b0467 ("PM: suspend: Do not pause
> cpuidle in the suspend-to-idle path"). This wasn't supposed to cause any
> negative impacts and also tested well on both Intel and ARM platforms.
> However this changed the semantics of when CPUs are allowed to be in the
> deepest state. For the AMD systems in question it appears this causes a
> firmware crash for timer based wakeup.
>
> It's hypothesized to be caused by the `amd-pmc` driver sending `OS_HINT`
> and all the CPUs going into a deep state while the timer is still being
> programmed. It's likely a firmware bug, but to avoid it don't allow setting
> CPUs into the deepest state while using CZN timer wakeup path.
>
> If later it's discovered that this also occurs from "regular" suspends
> without a timer as well or on other silicon, this may be later expanded to
> run in the suspend path for more scenarios.
>
> Cc: stable@xxxxxxxxxxxxxxx # 5.16+
> Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Link: https://lore.kernel.org/linux-acpi/BL1PR12MB51570F5BD05980A0DCA1F3F4E23A9@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/T/#mee35f39c41a04b624700ab2621c795367f19c90e
> Fixes: 8d89835b0467 ("PM: suspend: Do not pause cpuidle in the suspend-to-idle path")
> Fixes: 23f62d7ab25b ("PM: sleep: Pause cpuidle later and resume it earlier during system transitions")
> Fixes: 59348401ebed ("platform/x86: amd-pmc: Add special handling for timer based S0i3 wakeup"
> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Thank you for your patch, I've applied this patch to my review-hans
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans
I'll also add this to the pdx86/fixes branch and send a
fixes pull-req to Linus with this included.
Note it will show up in those branches once I've pushed my
local branch there, which might take a while.
Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.
Regards,
Hans
> ---
> changes from v2->v3:
> * Create a define for the latency value, and document it
> * Minor comment rewording
> * Add Rafael's tag
>
> drivers/platform/x86/amd-pmc.c | 42 ++++++++++++++++++++++++++--------
> 1 file changed, 33 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/platform/x86/amd-pmc.c b/drivers/platform/x86/amd-pmc.c
> index 4c72ba68b315..18b0f6ee65ce 100644
> --- a/drivers/platform/x86/amd-pmc.c
> +++ b/drivers/platform/x86/amd-pmc.c
> @@ -21,6 +21,7 @@
> #include <linux/module.h>
> #include <linux/pci.h>
> #include <linux/platform_device.h>
> +#include <linux/pm_qos.h>
> #include <linux/rtc.h>
> #include <linux/suspend.h>
> #include <linux/seq_file.h>
> @@ -85,6 +86,9 @@
> #define PMC_MSG_DELAY_MIN_US 50
> #define RESPONSE_REGISTER_LOOP_MAX 20000
>
> +/* QoS request for letting CPUs in idle states, but not the deepest */
> +#define AMD_PMC_MAX_IDLE_STATE_LATENCY 3
> +
> #define SOC_SUBSYSTEM_IP_MAX 12
> #define DELAY_MIN_US 2000
> #define DELAY_MAX_US 3000
> @@ -131,6 +135,7 @@ struct amd_pmc_dev {
> struct device *dev;
> struct pci_dev *rdev;
> struct mutex lock; /* generic mutex lock */
> + struct pm_qos_request amd_pmc_pm_qos_req;
> #if IS_ENABLED(CONFIG_DEBUG_FS)
> struct dentry *dbgfs_dir;
> #endif /* CONFIG_DEBUG_FS */
> @@ -521,6 +526,14 @@ static int amd_pmc_verify_czn_rtc(struct amd_pmc_dev *pdev, u32 *arg)
> rc = rtc_alarm_irq_enable(rtc_device, 0);
> dev_dbg(pdev->dev, "wakeup timer programmed for %lld seconds\n", duration);
>
> + /*
> + * Prevent CPUs from getting into deep idle states while sending OS_HINT
> + * which is otherwise generally safe to send when at least one of the CPUs
> + * is not in deep idle states.
> + */
> + cpu_latency_qos_update_request(&pdev->amd_pmc_pm_qos_req, AMD_PMC_MAX_IDLE_STATE_LATENCY);
> + wake_up_all_idle_cpus();
> +
> return rc;
> }
>
> @@ -538,24 +551,31 @@ static int __maybe_unused amd_pmc_suspend(struct device *dev)
> /* Activate CZN specific RTC functionality */
> if (pdev->cpu_id == AMD_CPU_ID_CZN) {
> rc = amd_pmc_verify_czn_rtc(pdev, &arg);
> - if (rc < 0)
> - return rc;
> + if (rc)
> + goto fail;
> }
>
> /* Dump the IdleMask before we send hint to SMU */
> amd_pmc_idlemask_read(pdev, dev, NULL);
> msg = amd_pmc_get_os_hint(pdev);
> rc = amd_pmc_send_cmd(pdev, arg, NULL, msg, 0);
> - if (rc)
> + if (rc) {
> dev_err(pdev->dev, "suspend failed\n");
> + goto fail;
> + }
>
> if (enable_stb)
> rc = amd_pmc_write_stb(pdev, AMD_PMC_STB_PREDEF);
> - if (rc) {
> + if (rc) {
> dev_err(pdev->dev, "error writing to STB\n");
> - return rc;
> + goto fail;
> }
>
> + return 0;
> +fail:
> + if (pdev->cpu_id == AMD_CPU_ID_CZN)
> + cpu_latency_qos_update_request(&pdev->amd_pmc_pm_qos_req,
> + PM_QOS_DEFAULT_VALUE);
> return rc;
> }
>
> @@ -579,12 +599,15 @@ static int __maybe_unused amd_pmc_resume(struct device *dev)
> /* Write data incremented by 1 to distinguish in stb_read */
> if (enable_stb)
> rc = amd_pmc_write_stb(pdev, AMD_PMC_STB_PREDEF + 1);
> - if (rc) {
> + if (rc)
> dev_err(pdev->dev, "error writing to STB\n");
> - return rc;
> - }
>
> - return 0;
> + /* Restore the QoS request back to defaults if it was set */
> + if (pdev->cpu_id == AMD_CPU_ID_CZN)
> + cpu_latency_qos_update_request(&pdev->amd_pmc_pm_qos_req,
> + PM_QOS_DEFAULT_VALUE);
> +
> + return rc;
> }
>
> static const struct dev_pm_ops amd_pmc_pm_ops = {
> @@ -722,6 +745,7 @@ static int amd_pmc_probe(struct platform_device *pdev)
> amd_pmc_get_smu_version(dev);
> platform_set_drvdata(pdev, dev);
> amd_pmc_dbgfs_register(dev);
> + cpu_latency_qos_add_request(&dev->amd_pmc_pm_qos_req, PM_QOS_DEFAULT_VALUE);
> return 0;
>
> err_pci_dev_put:
