Hello, this is the patch [1] as discussed on kernel bugzilla bug #13511 [2]. I'm including the original comments from the patch creator. [1] http://bugzilla.kernel.org/attachment.cgi?id=21889 [2] http://bugzilla.kernel.org/show_bug.cgi?id=13511 Hello. On the following model Manufacturer: Packard Bell BV Product Name: EasyNote_BG45-U-001CH BQC returns a value between 0 and 15 but the brightness levels are between 0 and 8. I could make a table of correspondance however I find it too inflexible. So I propose the following patch which disables BQC if it behaves badly -- Regards Vladimir 'phcoder' Serbinenko ["bad_bqc.patch" (text/x-patch)] diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index 1bdfb37..1735c34 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -594,6 +594,7 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device, unsigned long long *level) { acpi_status status = AE_OK; + int i; if (device->cap._BQC || device->cap._BCQ) { char *buf = device->cap._BQC ? "_BQC" : "_BCQ"; @@ -609,8 +610,15 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device, } *level += bqc_offset_aml_bug_workaround; - device->brightness->curr = *level; - return 0; + for (i = 2; i < device->brightness->count; i++) + if (device->brightness->levels[i] == *level) { + device->brightness->curr = *level; + return 0; + } + /* BQC returned an invalid level. Stop using it. */ + ACPI_WARNING((AE_INFO, "%s returned an invalid level", + buf)); + device->cap._BQC = device->cap._BCQ = 0; } else { /* Fixme: * should we return an error or ignore this failure?
Attachment:
bad_bqc.patch
Description: Binary data
