| Message ID | s5hppotrn5l.wl%tiwai@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi On Thu, Dec 19, 2013 at 2:22 PM, Takashi Iwai <tiwai@suse.de> wrote: > At Thu, 19 Dec 2013 13:36:38 +0100, > David Herrmann wrote: >> >> Hi >> >> On Thu, Dec 19, 2013 at 12:06 PM, Takashi Iwai <tiwai@suse.de> wrote: >> > At Thu, 19 Dec 2013 11:46:51 +0100, >> > David Herrmann wrote: >> >> >> >> Hi >> >> >> >> On Thu, Dec 19, 2013 at 1:03 AM, One Thousand Gnomes >> >> <gnomes@lxorguk.ukuu.org.uk> wrote: >> >> >> > That bug always existed, simplefb is just the first driver to hit it >> >> >> > (vesafb/efifb didn't use resources). I'm aware of the issue but as a >> >> >> > workaround you can simply disable CONFIG_X86_SYSFB. That restores >> >> >> > the old behavior. >> >> >> >> >> >> This looks like a regression, so we'll either need a fix or we'll have >> >> >> to mark CONFIG_X86_SYSFB as CONFIG_BROKEN. >> >> > >> >> > Kernel bugzilla has entries for simplefb breaking both vesafb and matrox >> >> > mga. >> >> >> >> Thanks for the hints. I've read through all I could find and tried to >> >> provide some help. >> >> >> >> I'm kind of confused, most of them enable CONFIG_X86_SYSFB (which is >> >> 'n' by default) but don't read the help text. I did my best to tell >> >> people that this option requires CONFIG_FB_SIMPLE, but if you don't >> >> read the help-text you won't notice that. Don't know what to do about >> >> that.. >> > >> > You can set FB_SIMPLE default value depending on X86_SYSFB, something >> > like: >> > >> > --- a/drivers/video/Kconfig >> > +++ b/drivers/video/Kconfig >> > @@ -2455,6 +2455,7 @@ config FB_HYPERV >> > config FB_SIMPLE >> > bool "Simple framebuffer support" >> > depends on (FB = y) >> > + default y if X86_SYSFB >> > select FB_CFB_FILLRECT >> > select FB_CFB_COPYAREA >> > select FB_CFB_IMAGEBLIT >> >> The "default <wx> if <yz>" only works if the config hasn't been set at >> all, yet. Even a "# CONFIG_* is unset" causes the "default" value to >> be ignored. > > Yes. I didn't suggest the strict dependency like below, just because > I assumed you didn't add it intentionally. It doesn't work. If CONFIG_FB=n this breaks. >> How about adding "depends on (FB_SIMPLE = y)" for X86_SYSFB? I guess I >> will try that and send a patch. > > That's in general a bad approach. If the strict dependency is > allowed, a more intuitive way is to give a reverse selection. But > then you'd need to correct the help text, too, as it's implemented > already as a dependency. Well, X86_SYSFB just changes the way x86-bootup code handles firmware-framebuffers. The option makes sense with CONFIG_FB=n or also CONFIG_DRM=n. However, currently the only driver that can profit from this is FB_SIMPLE. So I decided to set X86_SYSFB=n as default and no-one should ever bother (except for people who *really* want this). Unfortunately, people still enable it without understanding it. Changing FB_SIMPLE or other config options doesn't protect against that, instead I need to make X86_SYSFB fool-proof so it's only activated if people seriously *want* it. Doing a "select FB_SIMPLE" doesn't work due to the non-recursive behavior of "select". It will only enable FB_SIMPLE but not the dependencies of FB_SIMPLE (eg., FB). So I'm now left with "depends on (FB_SIMPLE = y)". And I actually like this, because there's no gain in using X86_SYSFB if you don't have FB_SIMPLE enabled. And it hides X86_SYSFB from all non-developers who currently shouldn't care anyway. Most sysfb code is enabled regardless of X86_SYSFB, the option really just controls the compatibility mode. And unless SimpleDRM is merged, there's little gain by setting it for non-developers. So I guess "depends on (FB_SIMPLE = y)" is the safest way. I will send a patch for that. If you're still not convinced, I'd be glad to hear your concerns. The only other idea I had is this: config X86_SYSFB bool "Mark VGA/VBE/EFI FB as generic system framebuffer" depends on (FB_SIMPLE = y) default y But I'm not sure I want the "default y" if FB_SIMPLE is active right now. We can add it later without any problems. Thanks David > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -2299,6 +2299,7 @@ source "drivers/rapidio/Kconfig" > > config X86_SYSFB > bool "Mark VGA/VBE/EFI FB as generic system framebuffer" > + select SIMPLE_FB > help > Firmwares often provide initial graphics framebuffers so the BIOS, > bootloader or kernel can show basic video-output during boot for > > > Takashi -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
--- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2299,6 +2299,7 @@ source "drivers/rapidio/Kconfig" config X86_SYSFB bool "Mark VGA/VBE/EFI FB as generic system framebuffer" + select SIMPLE_FB help Firmwares often provide initial graphics framebuffers so the BIOS, bootloader or kernel can show basic video-output during boot for