[LinuxBIOS] [PATCH] fix resource end in K8 amdk8/northbridge.c
marc.jones at amd.com
Fri Oct 12 23:36:36 CEST 2007
Rudolf Marek wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> Sorry for the delay.
> Uwe Hermann wrote:
>> On Sat, Sep 29, 2007 at 02:02:48AM +0200, Rudolf Marek wrote:
>>> Index: src/northbridge/amd/amdk8/northbridge.c
>>> --- src/northbridge/amd/amdk8/northbridge.c (revision 2776)
>>> +++ src/northbridge/amd/amdk8/northbridge.c (working copy)
>>> @@ -562,7 +562,7 @@
>>> base |= (resource->base >> 8) & 0xffffff00;
>>> base |= 3;
>>> limit &= 0x00000048;
>>> - limit |= ((resource->base + resource->size) >> 8) & 0xffffff00;
>>> + limit |= (resource_end(resource) >> 8) & 0xffffff00;
>>> limit |= (resource->index & 3) << 4;
>>> limit |= (nodeid & 7);
>>> f1_write_config32(reg + 0x4, limit);
>> What exactly is broken in the current code and how does it show? How can
>> we test the effect of the fix?
> Well I reverted the patch and have forgotten :/ Without the patch my machine
> suffers random lockup, when DMA from SATA/IDE hit the 0xC0000-0xCFFFF RAM memory.
> MMIO map: #5 0x00000a0000 - 0x00000cffff Access: R/W Dstnode:0 DstLink 0
> Mote the region size! it is 64kb larger than it should be...
> So with the patch applied, it gets correct again:
> MMIO map: #5 0x00000a0000 - 0x00000bffff Access: R/W Dstnode:0 DstLink 0
> Btw maybe you can take the util and put it to some SVN repo, it has proven useful ;)
I have looked this over and agree with Rudolf. The VGA area can't go
into the 0xC0000 ROM shadow area.
resource->base = 0xa0000;
resource->size = 0x20000;
limit |= ((resource->base + resource->size) >> 8) & 0xffffff00;
The problem is that the size is not base 0 aligned. The following would
also fix the bug and makes it more clear why it failed.
limit |= ((resource->base + (resource->size - 1)) >> 8) & 0xffffff00;
I think Rudolf's use of resource_end() is better than the inline math.
Senior Firmware Engineer
(970) 226-9684 Office
mailto:Marc.Jones at amd.com
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