On Thu, 04 Aug 2011 14:04:46 +0200 David wrote: > On Thursday 04 August 2011 07:55:16 you wrote: > > On Mit, 2011-08-03 at 17:55 -0700, Randy Dunlap wrote: > > > On Wed, 3 Aug 2011 18:55:41 GMT bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > > > > https://bugzilla.kernel.org/show_bug.cgi?id=40492 > > > > > > > > Summary: FB_BACKLIGHT should be set by > > > > BACKLIGHT_CLASS_DEVICE Product: Other > > > > Version: 2.5 > > > > > > > > Kernel Version: 3.0.0 > > > > > > > > Platform: All > > > > > > > > OS/Version: Linux > > > > > > > > Tree: Mainline > > > > > > > > Status: NEW > > > > > > > > Severity: normal > > > > Priority: P1 > > > > > > > > Component: Configuration > > > > > > > > AssignedTo: other_configuration@xxxxxxxxxxxxxxxxxxxx > > > > ReportedBy: StormByte@xxxxxxxxx > > > > Regression: No > > > > > > > > Created an attachment (id=67432) > > > > > > > > --> (https://bugzilla.kernel.org/attachment.cgi?id=67432) > > > > > > > > Kernel's config > > > > > > > > I discovered a scenario in which menuconfig fails to set > > > > FB_BACKLIGHT symbol when needed. > > > > > > > > In my case, I have propietary nvidia drivers once loaded Xorg, but > > > > in the meanwhile, I have configured an uvesafb framebuffer (thus, > > > > no other framebuffer active nor compiled). > > > > > > > > System works ok, but when trying to install nvidiabl[1] (to control > > > > nvidia's backlight) I find that FB_BACKLIGHT is not set where it > > > > should be because I have BACKLIGHT_CLASS_DEVICE set. > > > > > > > > The result is that nvidiabl does not compile. > > > > Sounds like an nvidiabl bug. I'm successfully using backlight control > > with radeon KMS with > > > > # CONFIG_FB_BACKLIGHT is not set > > CONFIG_BACKLIGHT_CLASS_DEVICE=m > > It does not seem a bug in nvidiabl, it needs this symbol in order to get 2 > defines (from include/linux/fb.h) > 394 #ifdef CONFIG_FB_BACKLIGHT > 395 /* Settings for the generic backlight code */ > 396 #define FB_BACKLIGHT_LEVELS 128 > 397 #define FB_BACKLIGHT_MAX 0xFF > 398 #endif > > I think nvidiabl uses those instead of having them hardcoded in its source, > and thus not a bug really. David, You could propose a patch that makes those 2 defines not be conditional on the CONFIB_FB_BACKLIGHT symbol. Or you could propose a patch that makes the FB_BACKLIGHT symbol user-configurable. Currently it is not user-configurable since it does not have a prompt string. I think all it would take is changing the "bool" line to include a prompt string and adding some help text. Something like (not tested, probably needs some wordsmithing): config FB_BACKLIGHT bool "Generic video backlight support" depends on FB select BACKLIGHT_LCD_SUPPORT select BACKLIGHT_CLASS_DEVICE default n help This option provides a little video backlight support. Most drivers that need it enable it automatically. --- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code *** -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
