From: Fabrizio Bertocci fabriziobertocci@gmail.com
commit 49201b90af818654c5506a0decc18e111eadcb66 upstream.
On some AMD hardware laptops, the system fails communicating with the PMC when entering s2idle and the machine is battery powered.
Hardware description: HP Pavilion Aero Laptop 13-be0097nr CPU: AMD Ryzen 7 5800U with Radeon Graphics GPU: 03:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Device [1002:1638] (rev c1)
Detailed description of the problem (and investigation) here: https://gitlab.freedesktop.org/drm/amd/-/issues/1799
Patch is a single line: reduce the polling delay in half, from 100uSec to 50uSec when waiting for a change in state from the PMC after a write command operation.
After changing the delay, I did not see a single failure on this machine (I have this fix for now more than one week and s2idle worked every single time on battery power).
Cc: stable@vger.kernel.org Acked-by: Shyam Sundar S K Shyam-sundar.S-k@amd.com Signed-off-by: Fabrizio Bertocci fabriziobertocci@gmail.com Link: https://lore.kernel.org/r/CADtzkx7TdfbwtaVEXUdD6YXPey52E-nZVQNs+Z41DTx7gqMqt... Signed-off-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/platform/x86/amd-pmc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/platform/x86/amd-pmc.c +++ b/drivers/platform/x86/amd-pmc.c @@ -70,7 +70,7 @@ #define AMD_CPU_ID_CZN AMD_CPU_ID_RN #define AMD_CPU_ID_YC 0x14B5
-#define PMC_MSG_DELAY_MIN_US 100 +#define PMC_MSG_DELAY_MIN_US 50 #define RESPONSE_REGISTER_LOOP_MAX 20000
#define SOC_SUBSYSTEM_IP_MAX 12