On Mon, Feb 1, 2010 at 6:46 PM, Luca Barbieri wrote:
>> Idea is to mask all move which involve TT (AGP) with the agp_caching_mask,
>> it's easy to do in radeon ttm layer code and i believe it's easy to do
>> in nouveau
>> too. On non AGP you set agp_caching_mask to UC|WC|CACHED.
>
> Sure, but isn'
On Mon, Feb 1, 2010 at 5:26 PM, Luca Barbieri wrote:
> I see a problem with this.
>
> If you have uncached TT (e.g. AGP) you want to get uncached for
> TT->SYSTEM, but you want cached for VRAM->SYSTEM.
> If you set SYSTEM to uncached, then VRAM->SYSTEM will broken, and if
> you set SYSTEM to cache
> Your patch remove the consistency of caching attribute and make move btw
> non fixed area different than others move, while driver can already achieve
> so.
It is already different, because TTM does it by changing the page
attributes, as opposed to copying data.
Thus, it is useful to preserve th
> Idea is to mask all move which involve TT (AGP) with the agp_caching_mask,
> it's easy to do in radeon ttm layer code and i believe it's easy to do
> in nouveau
> too. On non AGP you set agp_caching_mask to UC|WC|CACHED.
Sure, but isn't that uglier and much more ad-hoc that the patch I proposed?
I see a problem with this.
If you have uncached TT (e.g. AGP) you want to get uncached for
TT->SYSTEM, but you want cached for VRAM->SYSTEM.
If you set SYSTEM to uncached, then VRAM->SYSTEM will broken, and if
you set SYSTEM to cached, TT->SYSTEM will be broken.
If you set to uncached | cached, VR
> If you set to uncached | cached, VRAM->SYSTEM will still be broken
> because it will choose uncached.
Assuming VRAM is uncached and not WC of course.
The reasoning still holds if you replace all instances of "uncached" with WC.
---
Jerome Glisse wrote:
> On Mon, Feb 01, 2010 at 11:35:21AM +1000, Dave Airlie wrote:
>
>> On Thu, Jan 28, 2010 at 7:26 PM, Luca Barbieri
>> wrote:
>>
>>> Currently TTM tries to preserve the previous caching even for moves
>>> between unrelated memory spaces.
>>>
>>> This results for instan
On Mon, Feb 01, 2010 at 11:35:21AM +1000, Dave Airlie wrote:
> On Thu, Jan 28, 2010 at 7:26 PM, Luca Barbieri wrote:
> > Currently TTM tries to preserve the previous caching even for moves
> > between unrelated memory spaces.
> >
> > This results for instance in moves from VRAM to PCIE GART changi
On Thu, Jan 28, 2010 at 7:26 PM, Luca Barbieri wrote:
> Currently TTM tries to preserve the previous caching even for moves
> between unrelated memory spaces.
>
> This results for instance in moves from VRAM to PCIE GART changing
> system memory to WC state needlessly.
>
> This patch changes TTM t
Currently TTM tries to preserve the previous caching even for moves
between unrelated memory spaces.
This results for instance in moves from VRAM to PCIE GART changing
system memory to WC state needlessly.
This patch changes TTM to only try to preserve caching if moving from
system/TT to system/T
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