Bug#604096: Bug#601341: Bug#602418: #601341, #602418 and #604096 seem to be duplicates

[Jeremy Fitzhardinge <jeremy@goop.org>]

On 12/22/2010 10:35 AM, Konrad Rzeszutek Wilk wrote:
>> Thanks. S since the Debian kernel has has DRM/TTM from 2.6.33 I assume I
>> want the NEEDS_IOREMAP (95518271) version.
>>
>> I'm about to try my backport of devel/ttm.pci-api-v2 which contains:
>>         drm/ttm: Add ttm_tt_free_page
>>         ttm: Introduce a placeholder for DMA (bus) addresses.
>>         ttm: Utilize the dma_addr_t array for pages that are to in DMA32 pool.
>>         ttm: Expand (*populate) to support an array of DMA addresses.
>>         radeon/ttm/PCIe: Use dma_addr if TTM has set it.
>>         nouveau/ttm/PCIe: Use dma_addr if TTM has set it.
>>         radeon/PCIe: Use the correct index field.
>> plus:
>>         9551827190db ttm: Set VM_IO only on pages with TTM_MEMTYPE_FLAG_NEEDS_IOREMAP set.
>>         c54d5aa10b7a ttm: Change VMA flags if they != to the TTM flags.
>>         c07fbfd17e61 fbmem: VM_IO set, but not propagated
> Looks good.
>
>>         d541daf6b956 pvops: make pte_flags() go via pvops
> I've only hit that on a machine with a P4 Prescott with AGP. On nothing else - so
> it might not be required... If you don't have it you just get a bunch of WARN.

It is technically necessary, but in practice it will only matter if
things modify ptes with PAT bits set in them.  I'm in two minds about
it; we really need to benchmark the effect to see how much it matters.


    J