Bugzilla: PCI resource address mismatch

["Antonino A. Daplas" <adaplas@gmail.com>]

Ben Kibbey reported that vesafb has stopped working for him for kernels newer than
2.6.12. His display is completely blanked. After a long debugging session, we noted
that the address of resource 0 of his VGA controller as reported by lspci does not
match what is reported by the BIOS.

More details:

In the working kernel (2.6.12.x), vesafb correctly ioremap's the framebuffer memory
located at 0xff000000.  lspci reports the same thing:

PCI: Using IRQ router SIS [1039/0008] at 0000:00:01.0
PCI: Cannot allocate resource region 9 of bridge 0000:00:02.0
...
vesafb: framebuffer at 0xff000000, mapped to 0xc4080000, using 1875k, total 8192k
vesafb: mode is 800x600x16, linelength=1600, pages=7
vesafb: protected mode interface info at c7bd:0000
vesafb: scrolling: redraw
vesafb: Truecolor: size=0:5:6:5, shift=0:11:5:0
Console: switching to colour frame buffer device 100x37
fb0: VESA VGA frame buffer device

0000:01:00.0 VGA compatible controller: Silicon Integrated Systems [SiS] 530/620
PCI/AGP VGA Display Adapter (rev a2) (prog-if 00 [VGA])
	Subsystem: Silicon Integrated Systems [SiS] SiS530,620 GUI Accelerator+3D
	Flags: bus master, 66MHz, medium devsel, latency 32
	Memory at ff000000 (32-bit, prefetchable) [size=8M]
	Memory at e7ef0000 (32-bit, non-prefetchable) [size=64K]
	I/O ports at cc00 [size=128]
	Capabilities: <available only to root>

In the non-working kernel, his dmesg has this:

PCI: Using IRQ router SIS [1039/0008] at 0000:00:01.0
PCI: Cannot allocate resource region 9 of bridge 0000:00:02.0
PCI: Cannot allocate resource region 0 of device 0000:01:00.0
PCI: Ignore bogus resource 6 [0:0] of 0000:01:00.0
...
vesafb: framebuffer at 0xff000000, mapped to 0xc4080000, using 1875k, total
8192k
vesafb: mode is 800x600x16, linelength=1600, pages=7
vesafb: protected mode interface info at c7bd:0000
vesafb: pmi: set display start = c00c7c25, set palette = c00c7c99
vesafb: scrolling: ywrap using protected mode interface, yres_virtual=1200
vesafb: Truecolor: size=0:5:6:5, shift=0:11:5:0
vesafb: Mode is VGA compatible
Console: switching to colour frame buffer device 100x37
fb0: VESA VGA frame buffer device

Note the message "Cannot allocate resource region 0 of device 0000:01:00.0"
This is the framebuffer memory of his VGA controller.

His lspci reports:

0000:01:00.0 VGA compatible controller: Silicon Integrated Systems [SiS]
530/620 PCI/AGP VGA Display Adapter (rev a2) (prog-if 00 [VGA])
	Subsystem: Silicon Integrated Systems [SiS] SiS530,620 GUI Accelerator+3D
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping-
SERR- FastB2B-
	Status: Cap+ 66MHz+ UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort-
<MAbort- >SERR- <PERR-
	Latency: 32 (500ns min)
	Region 0: Memory at 10000000 (32-bit, prefetchable) [size=8M]
	Region 1: Memory at e7ef0000 (32-bit, non-prefetchable) [size=64K]
	Region 2: I/O ports at cc00 [size=128]
	Capabilities: <available only to root>

In the non-working kernel, the addresses do not match:

"vesafb: framebuffer at 0xff000000"

 vs

"Region 0: Memory at 10000000 (32-bit, prefetchable) [size=8M]"

He also tried hard-coding the address to 0x10000000 in vesafb.c, but he still
is not getting any display.

Any ideas?

Tony

PS: Please see http://bugzilla.kernel.org/show_bug.cgi?id=5769 for more details.