[REGRESSION] v3.12-rc1: i915_driver_load oopses when sysfb enabled

[David Herrmann]

Hi Tom

On Sun, Sep 8, 2013 at 11:38 AM, Tom Gundersen <teg at jklm.no> wrote:
> On Sun, Sep 8, 2013 at 2:13 AM, David Herrmann <dh.herrmann at gmail.com> wrote:
>> Hi
>>
>> On Sun, Sep 8, 2013 at 1:22 AM, Tom Gundersen <teg at jklm.no> wrote:
>>> Hi David,
>>>
>>> On Sat, Sep 7, 2013 at 11:57 PM, Tom Gundersen <teg at jklm.no> wrote:
>>>> On Sat, Sep 7, 2013 at 4:30 PM, David Herrmann <dh.herrmann at gmail.com> wrote:
>>>>> Attached are two patches. The first one should fix this issue, the
>>>>> second one is the rebased ioremap_wc() patch from the other thread.
>>>>>
>>>>> Does this fix the issue (and the speed-problems)?
>>>>
>>>> Sadly, no. I added a few printk's to verify that the function you
>>>> added is called (it is), but still the same oops.
>>>
>>> A few more datapoints:
>>>
>>> Triggers:
>>> X86_SYSFB=y and FB_SIMPLE=n (so no fbdev until i915 is loaded)
>>> X86_SYSFB=y and FB_SIMPLE=y
>>>
>>> Does not trigger:
>>> X86_SYSFB=y, FB_EFI=yes, and without the overflow fix (i.e., so we
>>> fall back to efifb)
>>> X86_SYSFB=n and FB_EFI=y
>>> X86_SYSFB=n and FB_EFI=n (so no fbdev until i915 is loaded)
>>>
>>> Does this make any sense?
>>
>> Thanks a lot for these results. I think I got it know. I will write a
>> patch that marks the resource as busy. See:
>>   kernel/resource.c iomem_map_sanity_check()
>> It also contains a hint that we should set this for driver-resources
>> which not directly map to hardware resources (such as veasfb and,
>> obviously, simplefb).
>>
>> Following a diff which hopefully fixes this. The other two patches
>> should still be required, though. I will try to write a proper patch
>> tomorrow.
>>
>> Thanks a lot for these extensive tests, Tom!
>
> No problem. Thanks for the fix, it works for me!

I finally got time to send the patches out. You're on CC on all of
them. They're unmodified so no need to test again.

Thanks for the feedback!
David