Re: Linux 2.6.27-rc5: System boot regression caused by commit a2bd7274b47124d2fc4dfdb8c0591f545ba749dd

Yinghai Lu
2008-08-31T17:54:22Z

On Sun, Aug 31, 2008 at 10:42 AM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
>
> On Sun, 31 Aug 2008, Rafael J. Wysocki wrote:
>>
>> Works, dmesg is at:
>> http://www.sisk.pl/kernel/debug/mainline/2.6.27-rc5/2.6.27-rc5-test.log
>
> That BAR is indeed "locked". Now that we try to reallocate it, you get
> this in the log:
>
> pci 0000:00:00.0: BAR 3: error updating (0x40000004 != 0xe0000004)
> pci 0000:00:00.0: BAR 3: error updating (high 0x000001 != 0x000000)
>
> ie now the code _tried_ to update the BAR to point to 0x1_4000_0000
> instead, but the hardware refused, and it is still at 0x0_e000_0000.
>
> So Yinghai's patch "worked", but it worked by doing nothing.
>
> See my earlier guess about locked read-only resources a few emails back.
> IOW, I'm not at all surprised. I really do suspect that that BAR is some
> very special "this is the HT->PCIE region" BAR.

so the code could allocate the 64 bit resource above 4g,...

wonder how the probe could find out the size of is 1fff_ffff..

YH