Re: [PATCH v7 00/15] PCI: Allocate 64-bit BARs above 4G when possible
From: Bjorn Helgaas
Date: Tue Jan 07 2014 - 13:47:01 EST
On Tue, Jan 7, 2014 at 3:46 AM, Daniel Vetter <daniel@xxxxxxxx> wrote:
> On Mon, Jan 06, 2014 at 05:55:12PM -0700, Bjorn Helgaas wrote:
>> This is basically v7 of Yinghai's patch series:
>> The goal is to try to put 64-bit BARs above 4G so we can preserve the
>> 32-bit bus address space for 32-bit BARs.
>> There are a whole bunch of AGP updates at the beginning because some AGP
>> devices have 64-bit BARs, but most of the AGP drivers read the aperture
>> bus address directly from the BAR, and they only handle 32-bit BARs.
>> Putting BARs above 4G would break those drivers, so we tried to fix them
>> up first. Yinghai fixed intel-gtt.c, and I made similar fixes to all
>> the other AGP drivers I could find.
>> Some of the AGP updates are related to the fact that most of the drivers
>> assume the PCI bus address is the same as the CPU physical address. For
>> example, they read the bus address from the BAR, then call ioremap() on
>> it. This is wrong, because ioremap() expects a CPU physical address,
>> not a bus address. In most cases, I think AGP devices are in simple
>> systems where (bus_address == CPU_physical_address), so these updates
>> probably don't fix any broken systems. I'm pretty sure there are more
>> things like this that should be fixed.
> Patches 4-11 are Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Thanks a lot! I added your Reviewed-by to those patches.
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