Hi, On 11-06-15 13:47, Pali Rohár wrote: > On Wednesday 10 June 2015 15:01:19 Hans de Goede wrote: >> Port the backlight selection logic to the new backlight interface >> selection API. >> >> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> >> --- >> drivers/platform/x86/dell-laptop.c | 6 ++---- >> 1 file changed, 2 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c >> index d688d80..db2e031 100644 >> --- a/drivers/platform/x86/dell-laptop.c >> +++ b/drivers/platform/x86/dell-laptop.c >> @@ -31,6 +31,7 @@ >> #include <linux/slab.h> >> #include <linux/debugfs.h> >> #include <linux/seq_file.h> >> +#include <acpi/video.h> >> #include "../../firmware/dcdbas.h" >> >> #define BRIGHTNESS_TOKEN 0x7d >> @@ -1921,10 +1922,7 @@ static int __init dell_init(void) >> &dell_debugfs_fops); >> >> #ifdef CONFIG_ACPI >> - /* In the event of an ACPI backlight being available, don't >> - * register the platform controller. >> - */ >> - if (acpi_video_backlight_support()) >> + if (acpi_video_get_backlight_type() != acpi_backlight_vendor) >> return 0; >> #endif >> > > Now I'm thinking... Is this correct condition? And do we need it? This > Dell backlight interface works even if ACPI or intel i915 driver > controls backlight. Why we should prevent dell-laptop.ko to register > Dell backlight interface if ACPI video already register one? And why not > prevent when intel i915 driver register another? 3 things: 1) This is mostly a cleanup series, it does not make any behavioral changes (other then renaming the kernelcmdline option and we've already discussed fixing that). 2) All 3 drivers ultimately bit-bang the same hardware, we really should have only one driver banging the hardware, so if (acpi_video_get_backlight_type() != acpi_backlight_vendor) return 0; Definitely is the right thing todo here. 3) You're right that the intel_backlight still registering even if acpi_video_get_backlight_type() != acpi_backlight_native is weird, but that is how it was before this series, and userspace prefers firmware type backlight sysfs entries over platform /raw ones so it will automatically pick the right one. We should consider not registering the backlight sysfs class interface from the intel code when acpi_video_get_backlight_type() != acpi_backlight_native but that is something for later... Regards, Hans ------------------------------------------------------------------------------ _______________________________________________ ibm-acpi-devel mailing list ibm-acpi-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/ibm-acpi-devel
