From: "Christian König" <christian.koenig@amd.com>
To: Dave Airlie <airlied@gmail.com>,
Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Dave Airlie <airlied@linux.ie>,
Thomas Hellstrom <thellstrom@vmware.com>,
nouveau <nouveau@lists.freedesktop.org>,
LKML <linux-kernel@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
Ben Skeggs <bskeggs@redhat.com>,
"Deucher, Alexander" <alexander.deucher@amd.com>
Subject: Re: [PATCH 09/17] drm/radeon: use common fence implementation for fences
Date: Tue, 22 Jul 2014 10:43:13 +0200 [thread overview]
Message-ID: <53CE2421.5040906@amd.com> (raw)
In-Reply-To: <CAPM=9tyD2ZbrcGDC3hfNb7qNdzsfnyD-ZwM7G-nOgxeu5YKuSg@mail.gmail.com>
Am 22.07.2014 06:05, schrieb Dave Airlie:
> On 9 July 2014 22:29, Maarten Lankhorst <maarten.lankhorst@canonical.com> wrote:
>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
>> ---
>> drivers/gpu/drm/radeon/radeon.h | 15 +-
>> drivers/gpu/drm/radeon/radeon_device.c | 60 ++++++++-
>> drivers/gpu/drm/radeon/radeon_fence.c | 223 ++++++++++++++++++++++++++------
>> 3 files changed, 248 insertions(+), 50 deletions(-)
>>
> From what I can see this is still suffering from the problem that we
> need to find a proper solution to,
>
> My summary of the issues after talking to Jerome and Ben and
> re-reading things is:
>
> We really need to work out a better interface into the drivers to be
> able to avoid random atomic entrypoints,
Which is exactly what I criticized from the very first beginning. Good
to know that I'm not the only one thinking that this isn't such a good idea.
> I'm sure you have some ideas and I think you really need to
> investigate them to move this thing forward,
> even it if means some issues with android sync pts.
Actually I think that TTMs fence interface already gave quite a good
hint how it might look like. I can only guess that this won't fit with
the Android stuff, otherwise I can't see a good reason why we didn't
stick with that.
> but none of the two major drivers seem to want the interface as-is so
> something needs to give
>
> My major question is why we need an atomic callback here at all, what
> scenario does it cover?
Agree totally. As far as I can see all current uses of the interface are
of the kind of waiting for a fence to signal.
No need for any callback from one driver into another, especially not in
atomic context. If a driver needs such a functionality it should just
start up a kernel thread and do it's waiting there.
This obviously shouldn't be an obstacle for pure hardware
implementations where one driver signals a semaphore another driver is
waiting for, or a high signal on an interrupt line directly wired
between two chips. And I think this is a completely different topic and
not necessarily part of the common fence interface we should currently
focus on.
Christian.
> Surely we can use a workqueue based callback to ask a driver to check
> its signalling, is it really
> that urgent?
>
> Dave.
next prev parent reply other threads:[~2014-07-22 8:43 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-09 12:29 [PATCH 00/17] Convert TTM to the new fence interface Maarten Lankhorst
2014-07-09 12:29 ` [PATCH 01/17] drm/ttm: add interruptible parameter to ttm_eu_reserve_buffers Maarten Lankhorst
2014-07-09 12:29 ` [PATCH 02/17] drm/ttm: kill off some members to ttm_validate_buffer Maarten Lankhorst
2014-07-09 12:29 ` [PATCH 03/17] drm/nouveau: add reservation to nouveau_gem_ioctl_cpu_prep Maarten Lankhorst
2014-07-09 12:29 ` [PATCH 04/17] drm/nouveau: require reservations for nouveau_fence_sync and nouveau_bo_fence Maarten Lankhorst
2014-07-09 12:29 ` [PATCH 05/17] drm/ttm: call ttm_bo_wait while inside a reservation Maarten Lankhorst
2014-07-09 12:29 ` [PATCH 06/17] drm/ttm: kill fence_lock Maarten Lankhorst
2014-07-09 12:29 ` [PATCH 07/17] drm/nouveau: rework to new fence interface Maarten Lankhorst
2014-07-09 12:29 ` [PATCH 08/17] drm/radeon: add timeout argument to radeon_fence_wait_seq Maarten Lankhorst
2014-07-09 12:29 ` [PATCH 09/17] drm/radeon: use common fence implementation for fences Maarten Lankhorst
2014-07-09 12:57 ` Deucher, Alexander
2014-07-09 13:23 ` [PATCH v2 " Maarten Lankhorst
2014-07-10 17:27 ` Alex Deucher
2014-07-22 4:05 ` [PATCH " Dave Airlie
2014-07-22 8:43 ` Christian König [this message]
2014-07-22 11:46 ` Daniel Vetter
2014-07-22 11:52 ` Daniel Vetter
2014-07-22 11:57 ` Daniel Vetter
2014-07-22 12:19 ` Christian König
2014-07-22 13:26 ` [Nouveau] " Daniel Vetter
2014-07-22 13:45 ` Christian König
2014-07-22 14:44 ` Maarten Lankhorst
2014-07-22 15:02 ` Christian König
2014-07-22 15:18 ` Maarten Lankhorst
2014-07-22 15:17 ` Daniel Vetter
2014-07-22 15:35 ` Christian König
2014-07-22 15:42 ` Daniel Vetter
2014-07-22 15:59 ` Christian König
2014-07-22 16:21 ` Daniel Vetter
2014-07-22 16:39 ` Christian König
2014-07-22 16:52 ` Daniel Vetter
2014-07-22 16:43 ` Daniel Vetter
2014-07-23 6:40 ` Maarten Lankhorst
2014-07-23 6:52 ` Christian König
2014-07-23 7:02 ` Daniel Vetter
2014-07-23 7:06 ` Maarten Lankhorst
2014-07-23 7:09 ` Daniel Vetter
2014-07-23 7:15 ` Christian König
2014-07-23 7:32 ` Maarten Lankhorst
2014-07-23 7:41 ` Christian König
2014-07-23 7:26 ` Christian König
2014-07-23 7:31 ` Daniel Vetter
2014-07-23 7:37 ` Christian König
2014-07-23 7:51 ` Maarten Lankhorst
2014-07-23 7:58 ` Christian König
2014-07-23 8:07 ` Daniel Vetter
2014-07-23 8:20 ` Christian König
2014-07-23 8:25 ` Maarten Lankhorst
2014-07-23 8:42 ` Daniel Vetter
2014-07-23 8:46 ` Christian König
2014-07-23 8:54 ` Daniel Vetter
2014-07-23 9:27 ` Christian König
2014-07-23 9:30 ` Daniel Vetter
2014-07-23 9:36 ` Christian König
2014-07-23 9:38 ` Maarten Lankhorst
2014-07-23 9:39 ` Christian König
2014-07-23 9:39 ` Daniel Vetter
2014-07-23 9:44 ` Daniel Vetter
2014-07-23 9:47 ` Christian König
2014-07-23 9:52 ` Daniel Vetter
2014-07-23 9:55 ` Maarten Lankhorst
2014-07-23 10:13 ` Christian König
2014-07-23 10:52 ` Daniel Vetter
2014-07-23 12:36 ` Christian König
2014-07-23 12:42 ` Daniel Vetter
2014-07-23 13:16 ` Maarten Lankhorst
2014-07-23 14:05 ` Maarten Lankhorst
2014-07-24 13:47 ` Christian König
2014-07-23 8:01 ` Daniel Vetter
2014-07-23 8:31 ` Christian König
2014-07-23 12:35 ` Rob Clark
2014-07-22 14:05 ` Maarten Lankhorst
2014-07-22 14:24 ` Christian König
2014-07-22 14:27 ` Maarten Lankhorst
2014-07-22 14:39 ` Christian König
2014-07-22 14:47 ` Maarten Lankhorst
2014-07-22 15:16 ` Christian König
2014-07-22 15:19 ` Daniel Vetter
2014-07-22 15:42 ` Alex Deucher
2014-07-22 15:48 ` Daniel Vetter
2014-07-22 19:14 ` Jesse Barnes
2014-07-23 9:47 ` [Nouveau] " Daniel Vetter
2014-07-23 15:37 ` Jesse Barnes
2014-07-22 11:51 ` Maarten Lankhorst
2014-07-09 12:29 ` [PATCH 10/17] drm/qxl: rework to new fence interface Maarten Lankhorst
2014-07-09 12:30 ` [PATCH 11/17] drm/vmwgfx: get rid of different types of fence_flags entirely Maarten Lankhorst
2014-07-09 12:30 ` [PATCH 12/17] drm/vmwgfx: rework to new fence interface Maarten Lankhorst
2014-07-09 12:30 ` [PATCH 13/17] drm/ttm: flip the switch, and convert to dma_fence Maarten Lankhorst
2014-07-09 12:30 ` [PATCH 14/17] drm/nouveau: use rcu in nouveau_gem_ioctl_cpu_prep Maarten Lankhorst
2014-07-09 12:30 ` [PATCH 15/17] drm/radeon: use rcu waits in some ioctls Maarten Lankhorst
2014-07-09 12:30 ` [PATCH 16/17] drm/vmwgfx: use rcu in vmw_user_dmabuf_synccpu_grab Maarten Lankhorst
2014-07-09 12:30 ` [PATCH 17/17] drm/ttm: use rcu in core ttm Maarten Lankhorst
[not found] ` <CAHbf0-HaFi0px7QGfBErKenH7wDU08B5mxo_QhFJdDPC4WBDrQ@mail.gmail.com>
2014-07-09 13:21 ` [PATCH 00/17] Convert TTM to the new fence interface Maarten Lankhorst
2014-07-10 21:37 ` Thomas Hellström
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