From 2d71ee0ce72f2597962fb2e66153f94d692142ba Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Sun, 23 Sep 2018 15:58:10 +0200 Subject: [PATCH] ACPI / LPSS: Add a device link from the GPU to the BYT I2C5 controller On some Bay Trail systems the GPU ACPI fwnode has power-resources which point to the PMIC, which is connected over the LPSS I2C5 controller. This one was quite nasty to debug, unlike on CHT where the same problem leads to errors like these: i2c_designware 808622C1:06: controller timed out ACPI Error: AE_ERROR, Returned by Handler for [UserDefinedRegion] ACPI Error: Method parse/execution failed \_SB.P18W._ON, AE_ERROR video LNXVIDEO:00: Failed to change power state to D0 On BYT the read-modify-write done by drivers/acpi/pmic/intel_pmic_xpower.c on the AXP288 PMIC register to change the power-resource state *seems* to succeed. But in reality, because the I2C controller has not been resumed yet, the read silently fails and returns the wrong value, where as the write does succeed, writing back the wrong value for all the other power-resources in the same register, turning off a bunch of them. Which of course does not end well. This commit adds a RPM consumer link from the GPU (which has a LNXVIDEO HID) to the BYT LPSS I2C5 controller, so that the I2C controller gets resumed before the GPU is resumed and thus before we try to change the power-resource. Signed-off-by: Hans de Goede Tested-by: Jarkko Nikula Reviewed-by: Andy Shevchenko Signed-off-by: Rafael J. Wysocki --- drivers/acpi/acpi_lpss.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c index fe37fd67331d..75672004db87 100644 --- a/drivers/acpi/acpi_lpss.c +++ b/drivers/acpi/acpi_lpss.c @@ -473,6 +473,7 @@ struct lpss_device_links { static const struct lpss_device_links lpss_device_links[] = { {"808622C1", "7", "80860F14", "3", DL_FLAG_PM_RUNTIME}, {"808622C1", "7", "LNXVIDEO", NULL, DL_FLAG_PM_RUNTIME}, + {"80860F41", "5", "LNXVIDEO", NULL, DL_FLAG_PM_RUNTIME}, }; static bool hid_uid_match(struct acpi_device *adev, -- 2.11.0