From 6025e2fae3dde3c3d789d08f8ceacbdd9f90d471 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Thu, 24 Oct 2019 23:57:23 +0200
Subject: [PATCH] ACPI: LPSS: Add dmi quirk for skipping _DEP check for some device-links
Git-commit: 6025e2fae3dde3c3d789d08f8ceacbdd9f90d471
Patch-mainline: v5.5-rc1
References: git-fixes bnc#1151927 5.3.17

The iGPU / GFX0 device's _PS0 method on the ASUS T200TA depends on the
I2C1 controller (which is connected to the embedded controller). But unlike
in the T100TA/T100CHI this dependency is not listed in the _DEP of the GFX0
device.

This results in the dev_WARN_ONCE(..., "Transfer while suspended\n") call
in i2c-designware-master.c triggering and the AML code not working as it
should.

This commit fixes this by adding a dmi based quirk mechanism for devices
which miss a _DEP, and adding a quirk for the LNXVIDEO depending on the
I2C1 device on the Asus T200TA.

Fixes: 2d71ee0ce72f ("ACPI / LPSS: Add a device link from the GPU to the BYT I2C5 controller")
Tested-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: 4.20+ <stable@vger.kernel.org> # 4.20+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/acpi/acpi_lpss.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index cd8cf3333f04..751ed38f2a10 100644
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -10,6 +10,7 @@
 #include <linux/acpi.h>
 #include <linux/clkdev.h>
 #include <linux/clk-provider.h>
+#include <linux/dmi.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/mutex.h>
@@ -463,6 +464,18 @@ struct lpss_device_links {
 	const char *consumer_hid;
 	const char *consumer_uid;
 	u32 flags;
+	const struct dmi_system_id *dep_missing_ids;
+};
+
+/* Please keep this list sorted alphabetically by vendor and model */
+static const struct dmi_system_id i2c1_dep_missing_dmi_ids[] = {
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "T200TA"),
+		},
+	},
+	{}
 };
 
 /*
@@ -478,7 +491,8 @@ static const struct lpss_device_links lpss_device_links[] = {
 	/* CHT iGPU depends on PMIC I2C controller */
 	{"808622C1", "7", "LNXVIDEO", NULL, DL_FLAG_PM_RUNTIME},
 	/* BYT iGPU depends on the Embedded Controller I2C controller (UID 1) */
-	{"80860F41", "1", "LNXVIDEO", NULL, DL_FLAG_PM_RUNTIME},
+	{"80860F41", "1", "LNXVIDEO", NULL, DL_FLAG_PM_RUNTIME,
+	 i2c1_dep_missing_dmi_ids},
 	/* BYT CR iGPU depends on PMIC I2C controller (UID 5 on CR) */
 	{"80860F41", "5", "LNXVIDEO", NULL, DL_FLAG_PM_RUNTIME},
 	/* BYT iGPU depends on PMIC I2C controller (UID 7 on non CR) */
@@ -577,7 +591,8 @@ static void acpi_lpss_link_consumer(struct device *dev1,
 	if (!dev2)
 		return;
 
-	if (acpi_lpss_dep(ACPI_COMPANION(dev2), ACPI_HANDLE(dev1)))
+	if ((link->dep_missing_ids && dmi_check_system(link->dep_missing_ids))
+	    || acpi_lpss_dep(ACPI_COMPANION(dev2), ACPI_HANDLE(dev1)))
 		device_link_add(dev2, dev1, link->flags);
 
 	put_device(dev2);
@@ -592,7 +607,8 @@ static void acpi_lpss_link_supplier(struct device *dev1,
 	if (!dev2)
 		return;
 
-	if (acpi_lpss_dep(ACPI_COMPANION(dev1), ACPI_HANDLE(dev2)))
+	if ((link->dep_missing_ids && dmi_check_system(link->dep_missing_ids))
+	    || acpi_lpss_dep(ACPI_COMPANION(dev1), ACPI_HANDLE(dev2)))
 		device_link_add(dev1, dev2, link->flags);
 
 	put_device(dev2);
-- 
2.16.4