[PATCH 3/3] acpi: sleep: Don't offer s2idle on AMD platforms without LPS0

[Mario Limonciello <mario.limonciello@amd.com>]

On some OEM platforms a BIOS option is offered that will set the
sleep mode between S3 and S2idle.  This option will change certain HW
behaviors.  When in S2idle mode, Linux works properly. However when S3 mode
is picked but the user chooses S2idle in Linux the platform may not be
properly resumed.

To avoid users getting into this situation, don't offer s2idle on AMD
systems missing the LPS0 device either by a BIOS option or by using the
acpi "no_sleep_lps0" module parameter.

Reported-by: Bjoren Dasse <bjoern.daase@gmail.com>
BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1824
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215387
Reviewed-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 drivers/acpi/x86/s2idle.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c
index a1626737e5e0..c3d35a42ac2f 100644
--- a/drivers/acpi/x86/s2idle.c
+++ b/drivers/acpi/x86/s2idle.c
@@ -363,6 +363,13 @@ static int validate_dsm(acpi_handle handle, const char *uuid, int rev, guid_t *d
 
 static bool acpi_s2idle_valid(void)
 {
+	/* AMD systems must have low level firmware support */
+	if (acpi_s2idle_vendor_amd())
+#if IS_ENABLED(CONFIG_AMD_PMC)
+		return lps0_device_handle && !sleep_no_lps0;
+#else
+		return false;
+#endif
 	return true;
 }
 
@@ -450,6 +457,9 @@ static int lps0_device_attach(struct acpi_device *adev,
 	if (!acpi_s2idle_vendor_amd())
 		acpi_ec_mark_gpe_for_wake();
 
+	/* reset these so we update valid */
+	s2idle_set_ops(&acpi_s2idle_ops_lps0);
+
 	return 0;
 }
 
-- 
2.25.1