[PATCH 0/1] Fix using rtcwake on Cezanne platforms

[PATCH 0/1] Fix using rtcwake on Cezanne platforms

[Mario Limonciello]

Vicamo reports that rtcwake is not working properly on 6.0 kernel, but
worked properly on 5.17 kernel.  He bisected it down to:

commit b0c07116c8943 ("platform/x86: amd-pmc: Avoid reading SMU version at
probe time")

The issue is that commit made it possible to issue a suspend where SMU
version isn't known, meaning amd-pmc can't decide whether to activate
behavior to add a timer value to the OS_HINT message.

This wasn't reproduced on AMD's side initially because the testing
scripts were reading the idle mask from debugfs which would cache the
value in the driver.

This patch ensures that SMU version has been read even if debugfs hasn't
been accessed so that rtcwake can work again.

Mario Limonciello (1):
  platform/x86/amd: pmc: Read SMU version during suspend on Cezanne
    systems

 drivers/platform/x86/amd/pmc.c | 7 +++++++
 1 file changed, 7 insertions(+)

-- 
2.34.1

[PATCH 1/1] platform/x86/amd: pmc: Read SMU version during suspend on Cezanne systems

[Mario Limonciello]

commit b0c07116c8943 ("platform/x86: amd-pmc: Avoid reading SMU version at
probe time") adjusted the behavior for amd-pmc to avoid reading the SMU version
at startup but rather on first use to improve boot time.

However the SMU version is also used to decide whether to place a timer based
wakeup in the OS_HINT message.  If the idlemask hasn't been read before this
message was sent then the SMU version will not have been cached.

Ensure the SMU version has been read before deciding whether or not to run this
codepath.

Cc: stable@vger.kernel.org # 6.0
Reported-by: You-Sheng Yang <vicamo.yang@canonical.com>
Tested-by: Anson Tsao <anson.tsao@amd.com>
Fixes: b0c07116c8943 ("platform/x86: amd-pmc: Avoid reading SMU version at probe time")
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 drivers/platform/x86/amd/pmc.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/platform/x86/amd/pmc.c b/drivers/platform/x86/amd/pmc.c
index ce859b300712b..96e790e639a21 100644
--- a/drivers/platform/x86/amd/pmc.c
+++ b/drivers/platform/x86/amd/pmc.c
@@ -663,6 +663,13 @@ static int amd_pmc_verify_czn_rtc(struct amd_pmc_dev *pdev, u32 *arg)
 	struct rtc_time tm;
 	int rc;
 
+	/* we haven't yet read SMU version */
+	if (!pdev->major) {
+		rc = amd_pmc_get_smu_version(pdev);
+		if (rc)
+			return rc;
+	}
+
 	if (pdev->major < 64 || (pdev->major == 64 && pdev->minor < 53))
 		return 0;
 
-- 
2.34.1

Re: [PATCH 1/1] platform/x86/amd: pmc: Read SMU version during suspend on Cezanne systems

[Hans de Goede]

Hi,

On 10/20/22 13:37, Mario Limonciello wrote:
> commit b0c07116c8943 ("platform/x86: amd-pmc: Avoid reading SMU version at
> probe time") adjusted the behavior for amd-pmc to avoid reading the SMU version
> at startup but rather on first use to improve boot time.
> 
> However the SMU version is also used to decide whether to place a timer based
> wakeup in the OS_HINT message.  If the idlemask hasn't been read before this
> message was sent then the SMU version will not have been cached.
> 
> Ensure the SMU version has been read before deciding whether or not to run this
> codepath.
> 
> Cc: stable@vger.kernel.org # 6.0
> Reported-by: You-Sheng Yang <vicamo.yang@canonical.com>
> Tested-by: Anson Tsao <anson.tsao@amd.com>
> Fixes: b0c07116c8943 ("platform/x86: amd-pmc: Avoid reading SMU version at probe time")
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

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

Note it will show up in my review-hans branch 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


> ---
>  drivers/platform/x86/amd/pmc.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/platform/x86/amd/pmc.c b/drivers/platform/x86/amd/pmc.c
> index ce859b300712b..96e790e639a21 100644
> --- a/drivers/platform/x86/amd/pmc.c
> +++ b/drivers/platform/x86/amd/pmc.c
> @@ -663,6 +663,13 @@ static int amd_pmc_verify_czn_rtc(struct amd_pmc_dev *pdev, u32 *arg)
>  	struct rtc_time tm;
>  	int rc;
>  
> +	/* we haven't yet read SMU version */
> +	if (!pdev->major) {
> +		rc = amd_pmc_get_smu_version(pdev);
> +		if (rc)
> +			return rc;
> +	}
> +
>  	if (pdev->major < 64 || (pdev->major == 64 && pdev->minor < 53))
>  		return 0;
>