acer-wmi: Add acpi_backlight=video quirk for the Acer KAV80

The acpi-video backlight interface on the Acer KAV80 is broken, and worse
it causes the entire machine to slow down significantly after a suspend/resume.

Blacklist it, and use the acer-wmi backlight interface instead. Note that
the KAV80 is somewhat unique in that it is the only Acer model where we
fall back to acer-wmi after blacklisting, rather then using the native
(e.g. intel) backlight driver. This is done because there is no native
backlight interface on this model.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1128309
Cc: stable@vger.kernel.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c
index 96a0b75c52c9..26c4fd1394da 100644
--- a/drivers/platform/x86/acer-wmi.c
+++ b/drivers/platform/x86/acer-wmi.c
@@ -579,6 +579,17 @@ static const struct dmi_system_id video_vendor_dmi_table[] __initconst = {
                         DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5741"),
                 },
         },
+        {
+                /*
+                 * Note no video_set_backlight_video_vendor, we must use the
+                 * acer interface, as there is no native backlight interface.
+                 */
+                .ident = "Acer KAV80",
+                .matches = {
+                        DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
+                        DMI_MATCH(DMI_PRODUCT_NAME, "KAV80"),
+                },
+        },
         {}
 };