Re: x86 git tree broken (bisected)

[Robert Hancock]

Rafael J. Wysocki wrote:
> On Monday, 14 of April 2008, Yinghai Lu wrote:
> > On Mon, Apr 14, 2008 at 1:21 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> > > On Monday, 14 of April 2008, Yinghai Lu wrote:
> > >  > On Sun, Apr 13, 2008 at 5:19 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> > >  > >
> > >  > > On Monday, 14 of April 2008, Yinghai Lu wrote:
> > >  > >  > On Sun, Apr 13, 2008 at 3:10 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> > >  > >  > >
> > >  > >  > > On Monday, 14 of April 2008, Yinghai Lu wrote:
> > >  > >  > >  > On Sun, Apr 13, 2008 at 9:12 AM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> > >  > >  > >  > ...
> > >  > >  > >  > >  > can you try to apply the patch i sent to you about agp bridge order
> > >  > >  > >  > >  > reading for buggy silicon?
> > >  > >  > >  > >  >
> > >  > >  > >  > >  > Please boot kernel with "debug"...
> > >  > >  > >  > >  >
> > >  > >  > >  > >  > I want to verify if you can get
> > >  > >  > >  > >  >
> > >  > >  > >  > >  > "
> > >  > >  > >  > >  > Aperture conflicts with PCI mapping.
> > >  > >  > >  > >  > "
> > >  > >  > >  > >  >
> > >  > >  > >  > >  > in your boot log...
> > >  > >  > >  > >
> > >  > >  > >  > >  It's not present in there:
> > >  > >  > >  > >
> > >  > >  > >  > >  rafael@albercik:~> grep Aperture failing-with-patch-dmesg.log
> > >  > >  > >  > >  Aperture too small (32 MB)
> > >  > >  > >  > >  Aperture from AGP @ de000000 size 4096 MB (APSIZE 0)
> > >  > >  > >  > >  Aperture too small (0 MB)
> > >  > >  > >  > >  agpgart: Aperture pointing to RAM
> > >  > >  > >  > >  agpgart: Aperture from AGP @ de000000 size 4096 MB
> > >  > >  > >  > >  agpgart: Aperture too small (0 MB)
> > >  > >  > >  > >
> > >  > >  > >  > >  Full dmesg output attached.
> > >  > >  > >  >
> > >  > >  > >  > please check attached debug patch. and check if you can change GART
> > >  > >  > >  > size in your BIOS setup to 64M instead of 32M
> > >  > >  > >
> > >  > >  > >  Hm, what tree am I supposed to apply it too:
> > >  > >  > >  (1) current x86 git
> > >  > >  > >  (2) current x86 git w/ some of your previous patches (which ones in this case)
> > >  > >  > >  (3) failing (old) x86 git
> > >  > >  > >  (4) failing (old) x86 git w/ some of your previous patches (which ones in this
> > >  > >  > >     case)?
> > >  > >  >
> > >  > >  > (1) current x86.git
> > >  > >
> > >  > >  Attached is dmesg output from current x86.git with debug_gart_checking.patch
> > >  > >  applied.
> > >  >
> > >  > please test the final one ... ...
> > >  >
> > >  > You should get back 64M memory back.
> > >
> > >  Tested (current x86.git), dmesg output attached.
> > thanks.
> >
> > looks good. as expected...
> >
> > Checking aperture...
> > AGP bridge at 00:04:00
> > Aperture from AGP @ de000000 old size 32 MB
> > Aperture size 4096 MB (APSIZE 0) is not right, using settings from NB
> > Aperture from AGP @ de000000 size 32 MB (APSIZE 0)
> > Node 0: aperture @ de000000 size 32 MB
> > Aperture too small (32 MB) than (64 MB)
> > ...
> > agpgart: Detected AGP bridge 20
> > Setting up ULi AGP.
> > agpgart: AGP aperture is 32M @ 0xde000000
>
> BTW, what exactly would be the benefit of increasing the aperture size, given
> that I use a PCI Express graphics adapter?

The kernel uses the AGP GART aperture as an IOMMU. If you have >4GB of 
RAM and lots of devices with DMA addressing limits, more GART space 
would help prevent the IOMMU space from being exhausted.
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