[solved] i810fb problem

anakin · 2007-04-22 14:12:09

When trying to enable the i810fb framebuffer driver on an arch machine running the standard kernel26 package despite agpgart is already inserted I'm getting a fatal agpgart error message thus avoiding the module to be loaded.

dmesg | grep -i ^i810fb
i810fb_alloc_fbmem: cannot acquire agpgart

lspci | grep -i vga
00:02.0 VGA compatible controller: Intel Corporation 82815 CGC [Chipset Graphics Controller] (rev 02)

Last edited by anakin (2007-04-26 13:21:26)

anakin · 2007-04-22 18:00:18

I've been digging through the driver source code and after some reading in the i810fb project site concerning the way agpgart works I'm under the impression it's some sort of memory sharing conflict due to both drm and i810fb trying to access the same memory region.

Last edited by anakin (2007-04-23 12:19:20)

anakin · 2007-04-23 12:15:44

As a matter of fact it turned out to be caused by intel_agp not being loaded in the correct order within the mkinitcpio image, appending intel_agp just before agpgart and i810fb to the MODULES array in mkinitcpio.conf made the trick, nevertheless there's a new problem now.

Although i810fb is now properly loaded into the kernel thus creating /dev/fb0 it always defaults to the standard 640x480 at 60 mode no matter what video option I pass to the kernel. I've tried everything from a simple video=i810fb:800x600 to video=i810fb:vram:4,xres:1024,yres:768,bpp:16,hsync1:48.948,hsync2:48.948,vsync1:60.729,vsync2:60.729,accel,hw_cur,mtrr which some guy I found while googling for this said worked for him.

patroclo7 · 2007-04-23 22:24:19

May be you have a laptop with a flat panel. In this case, I think that i810fb behaves as its derivative intelfb and accepts the vga= parameter (this behaviour is not documented anywhere, except in the code), determined according the table for vesafb that you can find in the grub default config file.

I am also under the impressione that intelfb did not work properly for me when used as a module: I needed to have it and intel_agp compiled into the kernel. I do not know if it is the same for i810fb.

anakin · 2007-04-24 11:38:39

patroclo7 wrote:

I am also under the impressione that intelfb did not work properly for me when used as a module: I needed to have it and intel_agp compiled into the kernel. I do not know if it is the same for i810fb.

Afterwards I realized this was also the problem with i810fb, whenever it was compiled as a module and included in the MODULES array of mkinitcpio.conf so that it would be present in the initram image the video=i810fb:... kernel parameter would produce no effect, i810fb would invariably be loaded without any parameters.

As a quick workaround for environments which must stick with the stock kernel26 package or otherwise can't compile a custom kernel placing all the options to i1810fb in modprobe.conf and loading it from rc.conf's MODULES array works just fine.

anakin · 2007-04-26 13:19:40

Another common issue with this framebuffer driver may disrupt normal X server behavior when using stock i810_drv.so. Both use kernel's agpgart for system memory mapping as these Intel graphic cards are onboard. X server may run into trouble while trying to access a memory region already being used by i810fb, thus using the voffset i810fb option you can force the module to start at a safe memory address unused by X server.

Read more here http://i810fb.sourceforge.net/howto/x83.html.

Arch Linux

#1 2007-04-22 14:12:09

[solved] i810fb problem

#2 2007-04-22 18:00:18

Re: [solved] i810fb problem

#3 2007-04-23 12:15:44

Re: [solved] i810fb problem

#4 2007-04-23 22:24:19

Re: [solved] i810fb problem

#5 2007-04-24 11:38:39

Re: [solved] i810fb problem

#6 2007-04-26 13:19:40

Re: [solved] i810fb problem

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