On 04/04/2023 19:04, Yang, Fei wrote:
Subject: Re: [Intel-gfx] [PATCH 7/7] drm/i915: Allow user to set cache at BO creation
On 01/04/2023 09:38, fei.yang@xxxxxxxxx wrote:
From: Fei Yang <fei.yang@xxxxxxxxx>
To comply with the design that buffer objects shall have immutable
cache setting through out its life cycle, {set, get}_caching ioctl's
are no longer supported from MTL onward. With that change caching
policy can only be set at object creation time. The current code
applies a default (platform dependent) cache setting for all objects.
However this is not optimal for performance tuning. The patch extends
the existing gem_create uAPI to let user set PAT index for the object
at creation time.
The new extension is platform independent, so UMD's can switch to
using this extension for older platforms as well, while {set,
get}_caching are still supported on these legacy paltforms for compatibility reason.
Cc: Chris Wilson <chris.p.wilson@xxxxxxxxxxxxxxx>
Cc: Matt Roper <matthew.d.roper@xxxxxxxxx>
Signed-off-by: Fei Yang <fei.yang@xxxxxxxxx>
Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>
Just like the protected content uAPI, there is no way for userspace to tell
this feature is available other than trying using it.
Given the issues with protected content, is it not thing we could want to add?
Sorry I'm not aware of the issues with protected content, could you elaborate?
There was a long discussion on teams uAPI channel, could you comment there if
any concerns?
https://teams.microsoft.com/l/message/19:f1767bda6734476ba0a9c7d147b928d1@thread.skype/1675860924675?tenantId=46c98d88-e344-4ed4-8496-4ed7712e255d&groupId=379f3ae1-d138-4205-bb65-d4c7d38cb481&parentMessageId=1675860924675&teamName=GSE%20OSGC&channelName=i915%20uAPI%20changes&createdTime=1675860924675&allowXTenantAccess=false
Thanks,
-Fei
We wanted to have a getparam to detect protected support and were told
to detect it by trying to create a context with it.
Now it appears trying to create a protected context can block for
several seconds.
Since we have to report capabilities to the user even before it creates
protected contexts, any app is at risk of blocking.
-Lionel
Thanks,
-Lionel
---
drivers/gpu/drm/i915/gem/i915_gem_create.c | 33 ++++++++++++++++++++
include/uapi/drm/i915_drm.h | 36 ++++++++++++++++++++++
tools/include/uapi/drm/i915_drm.h | 36 ++++++++++++++++++++++
3 files changed, 105 insertions(+)
