[PATCH RFC] fix dell wyse 3040 poweroff

[Alexey Lukyanchuk]

Dell wyse 3040 cat't poweroff aftet kernel 5.11.
It happens  because i915_driver_shutdown function.
Disabling of this function mitigate this problem.

Fixes: 440b354f3 ("drivers/gpu/drm:power off troubles on dell wyse 3040") 
Signed-off-by: Alexey Lukyanchuk <skif at skif-web.ru> 
---
There is trouble with i915_driver_shutdown function. After some diving I found that trouble looks like race condition in drm_atomic_get_connector_state function (drivers/gpu/drm/drm_atomic.c), maybe it linked to iterators. Now I fully exclude i915_driver_shutdown for wyse 3040 device.

Can any one comment on this one please ? 
---
 drivers/gpu/drm/i915/display/intel_quirks.c | 25 +++++++++++++++++++++
 drivers/gpu/drm/i915/i915_driver.c          |  3 +++
 drivers/gpu/drm/i915/i915_drv.h             |  1 +
 3 files changed, 29 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_quirks.c b/drivers/gpu/drm/i915/display/intel_quirks.c
index e415cd7c0..a6a549d48 100644
--- a/drivers/gpu/drm/i915/display/intel_quirks.c
+++ b/drivers/gpu/drm/i915/display/intel_quirks.c
@@ -60,6 +60,12 @@ static void quirk_no_pps_backlight_power_hook(struct drm_i915_private *i915)
 	drm_info(&i915->drm, "Applying no pps backlight power quirk\n");
 }
 
+static void quirk_wyse_3040_shutdown_fix(struct drm_i915_private *i915)
+{
+	i915->quirks |= QUIRK_WYSE_3040_SHUTDOWN_FIX;
+	drm_info(&i915->drm, "Applying wyse 3040 shutdown fix\n");
+}
+
 struct intel_quirk {
 	int device;
 	int subsystem_vendor;
@@ -85,6 +91,12 @@ static int intel_dmi_no_pps_backlight(const struct dmi_system_id *id)
 	return 1;
 }
 
+static int wyse_3040_shutdown_fix(const struct dmi_system_id *id)
+{
+	DRM_INFO("This device need help with poweroff %s\n", id->ident);
+	return 1;
+}
+
 static const struct intel_dmi_quirk intel_dmi_quirks[] = {
 	{
 		.dmi_id_list = &(const struct dmi_system_id[]) {
@@ -131,6 +143,19 @@ static const struct intel_dmi_quirk intel_dmi_quirks[] = {
 		},
 		.hook = quirk_no_pps_backlight_power_hook,
 	},
+	{
+		.dmi_id_list = &(const struct dmi_system_id[]) {
+			{
+				.callback = wyse_3040_shutdown_fix,
+				.ident = "Dell Inc. 0G56C0",
+				.matches = {DMI_EXACT_MATCH(DMI_BOARD_VENDOR, "Dell Inc."),
+					    DMI_EXACT_MATCH(DMI_BOARD_NAME, "0G56C0"),
+				},
+			},
+			{ }
+		},
+		.hook = quirk_wyse_3040_shutdown_fix,
+	},
 };
 
 static struct intel_quirk intel_quirks[] = {
diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
index deb8a8b76..af60fb79a 100644
--- a/drivers/gpu/drm/i915/i915_driver.c
+++ b/drivers/gpu/drm/i915/i915_driver.c
@@ -1079,6 +1079,9 @@ static void intel_shutdown_encoders(struct drm_i915_private *dev_priv)
 
 void i915_driver_shutdown(struct drm_i915_private *i915)
 {
+	if (!(i915->quirks & QUIRK_WYSE_3040_SHUTDOWN_FIX))
+		return;
+
 	disable_rpm_wakeref_asserts(&i915->runtime_pm);
 	intel_runtime_pm_disable(&i915->runtime_pm);
 	intel_power_domains_disable(i915);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 086bbe894..fdd6866e7 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -200,6 +200,7 @@ struct drm_i915_display_funcs {
 #define QUIRK_INCREASE_T12_DELAY (1<<6)
 #define QUIRK_INCREASE_DDI_DISABLED_TIME (1<<7)
 #define QUIRK_NO_PPS_BACKLIGHT_POWER_HOOK (1<<8)
+#define QUIRK_WYSE_3040_SHUTDOWN_FIX (1<<9)
 
 struct i915_suspend_saved_registers {
 	u32 saveDSPARB;
-- 
2.25.1