linux/drivers/platform/x86/amd/pmc
Mario Limonciello 9f5595d5f0
platform/x86/amd: pmc: Require at least 2.5 seconds between HW sleep cycles
When an APU exits HW sleep with no active wake sources the Linux kernel will
rapidly assert that the APU can enter back into HW sleep. This happens in a
few ms. Contrasting this to Windows, Windows can take 10s of seconds to
enter back into the resiliency phase for Modern Standby.

For some situations this can be problematic because it can cause leakage
from VDDCR_SOC to VDD_MISC and force VDD_MISC outside of the electrical
design guide specifications. On some designs this will trip the over
voltage protection feature (OVP) of the voltage regulator module, but it
could cause APU damage as well.

To prevent this risk, add an explicit sleep call so that future attempts
to enter into HW sleep will have enough time to settle. This will occur
while the screen is dark and only on cases that the APU should enter HW
sleep again, so it shouldn't be noticeable to any user.

Cc: stable@vger.kernel.org
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Acked-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Link: https://lore.kernel.org/r/20250414162446.3853194-1-superm1@kernel.org
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
2025-04-17 14:14:39 +03:00
..
Kconfig x86/amd_nb: Move SMN access code to a new amd_node driver 2025-01-08 10:59:44 +01:00
Makefile platform/x86: amd: Use *-y instead of *-objs in Makefiles 2025-02-24 17:15:02 +02:00
mp1_stb.c platform/x86/amd/pmc: Add STB support for AMD Desktop variants 2024-12-02 19:47:21 +02:00
mp2_stb.c platform/x86/amd/pmc: Fix implicit declaration error on i386 2024-04-29 10:52:02 +02:00
pmc-quirks.c platform/x86/amd/pmc: Extend Framework 13 quirk to more BIOSes 2024-04-17 17:05:30 +03:00
pmc.c platform/x86/amd: pmc: Require at least 2.5 seconds between HW sleep cycles 2025-04-17 14:14:39 +03:00
pmc.h platform/x86/amd/pmc: Move macros and structures to the PMC header file 2025-03-07 12:17:48 +02:00