Hi (hint: your mail header seems to drop Reference-to/Reply-to headers and breaks thread-info) On Fri, Aug 16, 2013 at 8:45 PM, Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> wrote: > > >> -----Original Message----- >> From: David Herrmann [mailto:dh.herrmann@xxxxxxxxx] >> Sent: Friday, August 16, 2013 9:46 AM >> To: Haiyang Zhang >> Cc: linux-fbdev@xxxxxxxxxxxxxxx; driverdev-devel@xxxxxxxxxxxxxxxxxxxxxx; >> Tomi Valkeinen; Jean-Christophe Plagniol-Villard; akpm@linux- >> foundation.org; KY Srinivasan >> Subject: Re: source code file for the generic vga driver? >> >> Hi >> >> On Mon, Aug 5, 2013 at 9:12 PM, Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> >> wrote: >> > Hi folks, >> > >> > I'm working on an issue of HyperV synthetic frame buffer driver, which >> > seems to have a conflict with the generic vga driver (not the vesa >> > driver). I hope to read and trace into the source code for the generic vga >> driver... >> > >> > Can anyone point me to the source code file for the generic vga driver in >> the kernel tree? >> >> Everything lives in ./drivers/video/. The drivers you're probably interested in >> are "vesafb.c" or "vga16fb.c". There is also the "vgacon" driver >> in ./drivers/video/console/vgacon.c. I am not sure which one you are talking >> about. >> >> You might also want to have a look at the x86 sysfb infrastructure which isn't >> merged, yet: >> http://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/log/?h=x86/fb >> It provides proper platform-devices so drivers no longer conflict on the >> vga/vesa/efi.. framebuffer resources. It's x86 only as all the relevant drivers >> only work on x86. >> >> If you give some more information on what you are trying to do, I can point >> you to the relevant resources. My guess is that you want to have a look at >> remove_conflicting_framebuffers() in ./drivers/video/fbmem.c. > > Thank you for the detailed reply! > > I'm looking at a problem of Hyper-V synthetic fb driver (hyperv_fb) which seems > to have conflict with some kind of generic video driver. I'm not sure which driver > is this. > > On Suse, the vesafb is removed automatically by remove_conflicting_framebuffers() > when hyperv_fb is loaded. We don't have any problem here. > > On some other Distros, like RHEL, CentOS, Ubuntu, the generic driver seems not > to be vesafb -- I can't see any /dev/fb* there. And, the generic video driver seems not be > removed when hyperv_fb is loaded. This generic video driver is not vesafb or vga16fb or > vgacon, because it supports x-window GUI, and it's still here after I un-configured vesafb > and vga16fb. > > Could point out what is the generic video driver used by RHEL, Ubuntu by default? And, > how to let it exit automatically when our FB driver (hyperv_fb) is loaded? I have no idea what RHEL or Ubuntu use, sorry. But your description sounds odd. The kernel has 3 different places that could use VGA resources: - fbdev drivers (/dev/fbX or /sys/class/graphics) - DRM drivers (/dev/dri/cardX or /sys/class/drm) - vgacon Could you check whether these directories are empty? (/sys/class/graphics/ and /sys/class/drm/ on a running machine) If these are empty, this doesn't look like a kernel thing. Are you sure it's a kernel driver that accesses your VGA resources? The xserver used to have some pretty huge vga/vesa/.. user-space drivers. Could you tell me whether the linux-console actually works? That is, do you get some console output if xserver is not running? Cheers David _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
