Re: Info: mapping multiple BARs. Your kernel is fine.

[Dave Jones <davej@redhat.com>]

On Thu, Apr 17, 2014 at 12:26:37PM -0600, Bjorn Helgaas wrote:
 > Thanks a lot for testing this out and debugging my issues.
 > 
 > Here's a new version that looks for both device IDs I know about.

I can confirm this patch does fix the backtrace.
I disabled lockdep, and now I can get to X each boot, but I still see
a black screen rather than a console between modesetting becoming active, and X starting.

(The lockdep thing turned out to be a known XFS false positive, but for
 some reason it actually caused X to lock up)

 > I'm still nervous about the modeset problem Dave is seeing.  Since the
 > original patch wouldn't find an 8086:0c00 device on Dave's system, it
 > should have done nothing.  But since it caused a modesetting problem,
 > there's something else doing on that I don't understand.

I don't know if it's relevant, but this laptop (and I suspect many other
thinkpads which seem affected) have dual gfx, both show up on the bus,
even if though the nvidia isn't in use..

00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09) (prog-if 00 [VGA controller])
        Subsystem: Lenovo Device 2200
        Flags: bus master, fast devsel, latency 0, IRQ 44
        Memory at f1000000 (64-bit, non-prefetchable) [size=4M]
        Memory at e0000000 (64-bit, prefetchable) [size=256M]
        I/O ports at 6000 [size=64]
        Expansion ROM at <unassigned> [disabled]
        Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
        Capabilities: [d0] Power Management version 2
        Capabilities: [a4] PCI Advanced Features
        Kernel driver in use: i915

01:00.0 3D controller: NVIDIA Corporation GF117M [GeForce 610M/710M/820M / GT 620M/625M/630M/720M] (rev a1)
        Subsystem: Lenovo NVS 5200M
        Flags: bus master, fast devsel, latency 0, IRQ 11
        Memory at f0000000 (32-bit, non-prefetchable) [size=16M]
        Memory at c0000000 (64-bit, prefetchable) [size=256M]
        Memory at d0000000 (64-bit, prefetchable) [size=32M]
        I/O ports at 5000 [size=128]
        Expansion ROM at <ignored> [disabled]
        Capabilities: [60] Power Management version 3
        Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+
        Capabilities: [78] Express Endpoint, MSI 00
        Capabilities: [b4] Vendor Specific Information: Len=14 <?>
        Capabilities: [100] Virtual Channel
        Capabilities: [128] Power Budgeting <?>
        Capabilities: [600] Vendor Specific Information: ID=0001 Rev=1 Len=024 <?>

Just as X starts up, I see this in dmesg..

[   42.879049] [drm:cpt_serr_int_handler] *ERROR* PCH transcoder A FIFO underrun

	Dave