Re: i915-related and general system freezes with specific kernelconfig // IOMMU

From: Mihai Moldovan
Date: Sat Jan 19 2013 - 11:26:25 EST


* On 19.01.2013 05:13 PM, Mihai Moldovan wrote:
> * On 19.01.2013 02:27 PM, Daniel Vetter wrote:
>> You have a gen4.5 chipset which is known to be utterly broken for
>> IOMMU+intel gpu.
> Nice description for what I'm seeing. ;)
>
> After some more hours of uptime I'm inclined to say, that "intel_iommu=off
> iommu=off" fixes my random freezes as well.
> Alas, the USB and PCI(e) problems are still around, but I could test recompiling
> 3.7.2 with Intel IOMMU turned off completely in the kernel config.
> Interestingly, my 3.0.2 kernel which worked fine for so long doesn't even *have*
> support for VT-d/Intel IOMMU. This could explain why I wasn't bit by those
> problems on all previous versions.
>
>
>> [...] and we've never added the proper
>> quirks. See https://bugzilla.kernel.org/show_bug.cgi?id=51921 for a
>> proposed patch to fix this (i.e. automatically set
>> intel_iommu=igfx_off for affected platfroms). Testing highly welcome.
> From a quick glance, I don't think this patch will work as-is, my PCI ID 2e12 is
> missing.
> [...]

Which of course will work, as 2e10 is my DRAM controller as reported by lspci,
sorry.

But, shouldn't the
"DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2eXX, quirk_iommu_rwbf);"
calls be rather
" DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2e00, quirk_iommu_g4x_gfx);"
?

The current patch errors out on my while compiling as quirk_iommu_rwbf is not
yet defined at that place.

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