On 11/06/2013 09:07 AM, Aaron Lu wrote: > Some firmware doesn't initialize initial backlight level to a proper > value and _BQC will return 0 on first time evaluation. We used to be > able to detect such incorrect value with our code logic, as value 0 > normally isn't a valid value in _BCL. But with the introduction of Win8, > firmware begins to fill _BCL with values from 0 to 100, now 0 becomes > a valid value but that value will make user's screen black. This patch > test initial _BQC for value 0, if such a value is returned, do not use > it. > > Reference: https://bugzilla.kernel.org/show_bug.cgi?id=64031 > Reference: https://bugzilla.kernel.org/show_bug.cgi?id=61231 > Reference: https://bugzilla.kernel.org/show_bug.cgi?id=63111 > Reported-by: Qingshuai Tian <qingshuai.tian@xxxxxxxxx> > Tested-by: Aaron Lu <aaron.lu@xxxxxxxxx> on "Idealpad u330p" > Reported-and-tested-by: <erno@xxxxxx> on "Acer Aspire V5-573G" > Reported-and-tested-by: Kirill Tkhai <tkhai@xxxxxxxxx> on "HP 250 G1" With this patch applied, we do not need commit e37f14a5fb85 "ACPI / video: Ignore BIOS initial backlight value for HP 250 G1" any more. So I made a revert patch on top of the two. From: Aaron Lu <aaron.lu@xxxxxxxxx> Subject: [PATCH] Revert "ACPI / video: Ignore BIOS initial backlight value for HP 250 G1" This reverts commit e37f14a5fb85522f3bbf88ece6134c4e610ed598. It turned out other systems also share the same problem with bug 63111 so I made a patch to catch initial brightness level 0 problem. With that patch applied, we do not need to place HP 250 G1 in DMI table. Signed-off-by: Aaron Lu <aaron.lu@xxxxxxxxx> --- drivers/acpi/video.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index a049fa9360d0..18dbdff4656e 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -504,14 +504,6 @@ static struct dmi_system_id video_dmi_table[] __initdata = { DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion m4 Notebook PC"), }, }, - { - .callback = video_ignore_initial_backlight, - .ident = "HP 250 G1", - .matches = { - DMI_MATCH(DMI_BOARD_VENDOR, "Hewlett-Packard"), - DMI_MATCH(DMI_PRODUCT_NAME, "HP 250 G1 Notebook PC"), - }, - }, {} }; -- 1.8.4.39.ga0d3f10 > Signed-off-by: Aaron Lu <aaron.lu@xxxxxxxxx> > Cc: stable <stable@xxxxxxxxxxxxxxx> > --- > drivers/acpi/video.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c > index bf521b36c2f9..a049fa9360d0 100644 > --- a/drivers/acpi/video.c > +++ b/drivers/acpi/video.c > @@ -858,7 +858,7 @@ acpi_video_init_brightness(struct acpi_video_device *device) > for (i = 2; i < br->count; i++) > if (level == br->levels[i]) > break; > - if (i == br->count) > + if (i == br->count || !level) > level = max_level; > } > > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
