Re: pci regression: "panic: resource_list_alloc: resource entry is busy"

On Tuesday 03 March 2009 9:03:24 pm Michael Butler wrote:
> Post SVN rev 189306 on my Toshiba laptop, I get a bootstrap panic as
> follows:
> 
> vgapci0: <VGA-compatible display> port 0x1800-0x1807
> 	mem 0xf0a00000-0xf0a7ffff,0xd0000000-0xdfffffff,
> 	0xf0b00000-0xf0b3ffff
> 	irq 16 at device 2.0 on pci0
> acpi_video0: <ACPI video extension> on vgapci0
> 	found VGA CRT or VESA Compatible Analog Monitor(100), idx#0,
> 	port#0, detectable by BIOS, head #0
> 	found TV/HDTV or Analog-Video Monitor(200), idx#0,
> 	port#0, detectable by BIOS, head #0
> 	found Internal/Integrated Digital Flat Panel(400), idx#0,
> 	port#0, detectable by BIOS, head #0
> agp0: <Intel 82945GM (945GM GMCH) SVGA controller> on vgapci0
> vgapci0: Reserved 0x10000000 bytes for rid 0x18 type 3 at 0xd0000000
> vgapci0: Reserved 0x80000 bytes for rid 0x10 type 3 at 0xf0a00000
> vgapci0: Reserved 0x40000 bytes for rid 0x1c type 3 at 0xf0b00000
> agp0: detected 7932k stolen memory
> agp0: aperture size is 256M
> drm0: <Intel i945GM> on vgapci0
> 
> <<< fails here with "panic: resource_list_alloc: resource entry is busy"
> 
> vgapci0: Reserved 0x80000 bytes for rid 0x10 type 3 at 0xf0a00000
> vgapci0: child drm0 requested pci_enable_busmaster
> info: [drm] AGP at 0xd0000000 256MB
> info: [drm] Initialized i915 1.6.0 20080730
> vgapci1: <VGA-compatible display> mem 0xf0a80000-0xf0afffff at
> 	device 2.1 on pci0
> 
> Presumably, the agp/drm interaction with vgapci resources prompts this :-(

Hmmm, so the issue is that agp0 and drm0 are both allocating the same BAR.  I 
can probably make this work with some patches to vgapci to have it proxy the 
requests and share the resources.

-- 
John Baldwin