> -----Original Message----- > From: David Herrmann [mailto:dh.herrmann@xxxxxxxxx] > Sent: Friday, August 16, 2013 4:40 PM > To: Haiyang Zhang > Cc: linux-fbdev@xxxxxxxxxxxxxxx; driverdev-devel@xxxxxxxxxxxxxxxxxxxxxx; > Tomi Valkeinen; Jean-Christophe Plagniol-Villard; akpm@linux- > foundation.org; KY Srinivasan > Subject: Re: conflict of hyperv_fb and the generic video driver? > > Hi > > On Fri, Aug 16, 2013 at 10:27 PM, Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > wrote: > > > > > >> -----Original Message----- > >> From: David Herrmann [mailto:dh.herrmann@xxxxxxxxx] > >> Sent: Friday, August 16, 2013 3:11 PM > >> To: Haiyang Zhang > >> Cc: linux-fbdev@xxxxxxxxxxxxxxx; > >> driverdev-devel@xxxxxxxxxxxxxxxxxxxxxx; > >> Tomi Valkeinen; Jean-Christophe Plagniol-Villard; akpm@linux- > >> foundation.org; KY Srinivasan > >> Subject: Re: conflict of hyperv_fb and the generic video driver? > >> > >> 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? > > > > To find out the default driver, I manually removed my hyperv_fb driver. > > The vesafb is unconfigured: > > # CONFIG_FB_BOOT_VESA_SUPPORT is not set # CONFIG_FB_UVESA is > not set > > # CONFIG_FB_VESA is not set > > > > But I saw VESA VBE in the x log. Seems it's the default driver: > > "/var/log/Xorg.0.log": > > [ 12.340] (II) VESA(0): Primary V_BIOS segment is: 0xc000 > > [ 12.341] (II) VESA(0): VESA BIOS detected > > [ 12.341] (II) VESA(0): VESA VBE Version 2.0 > > [ 12.341] (II) VESA(0): VESA VBE Total Mem: 4096 kB > > [ 12.341] (II) VESA(0): VESA VBE OEM: IBM SVGA BIOS, (C) 1993 > International Business Machines > > [ 12.341] (II) VESA(0): VESA VBE OEM Software Rev: 0.0 > > [ 12.365] (II) VESA(0): Creating default Display subsection in Screen > section > > "Default Screen Section" for depth/fbbpp 24/32 > > [ 12.365] (==) VESA(0): Depth 24, (--) framebuffer bpp 32 > > [ 12.365] (==) VESA(0): RGB weight 888 > > [ 12.365] (==) VESA(0): Default visual is TrueColor > > [ 12.365] (==) VESA(0): Using gamma correction (1.0, 1.0, 1.0) > > > > There is no /dev/fb*, /dev/dri/, /sys/class/drm I see > > /sys/class/graphics/fbcon is here. But console output is not working. > > > > Seems that the VESA VBE is causing conflict with my driver... Is there > > any way to disable VESA VBE driver? > > This is the Xorg vesa driver. There is no way to detect that from the kernel (at > least no sane way). Just uninstall the vesa driver, no one uses that these days. > At least I see no reason why you would use it. > Probably named xf86-video-vesa. Or make sure your hyperv fbdev driver is > loaded before xorg starts and then load xf86-video-fbdev over xf86-video- > vesa. Removing the xorg vesa driver has solved the conflict. Also, I found adding a xorg.conf which specifies fbdev can solve the problem too: [root@localhost ~]# cat /etc/X11/xorg.conf Section "Device" Identifier "HYPER-V Framebuffer" Driver "fbdev" EndSection Thank you SO MUCH for the help!! - Haiyang _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
