On 03.05.2012 18:34, Jerome Glisse wrote: > On Thu, May 3, 2012 at 12:29 PM, Alex Deucher<alexdeucher at gmail.com> > wrote: >> On Thu, May 3, 2012 at 11:56 AM, Jerome Glisse<j.glisse at gmail.com> wrote: >>> On Thu, May 3, 2012 at 7:39 AM, Christian K?nig<deathsimple at vodafone.de> >>> wrote: >>>> On 03.05.2012 09:21, Michel D?nzer wrote: >>>>> On Mit, 2012-05-02 at 16:20 -0400, j.glisse at gmail.com wrote: >>>>>> From: Jerome Glisse<jglisse at redhat.com> >>>>>> >>>>>> This convert fence to use uint64_t sequence number intention is >>>>>> to use the fact that uin64_t is big enough that we don't need to >>>>>> care about wrap around. >>>>>> >>>>>> Tested with and without writeback using 0xFFFFF000 as initial >>>>>> fence sequence and thus allowing to test the wrap around from >>>>>> 32bits to 64bits. >>>>>> >>>>>> Signed-off-by: Jerome Glisse<jglisse at redhat.com> >>>>> [...] >>>>> >>>>>> diff --git a/drivers/gpu/drm/radeon/radeon_fence.c >>>>>> b/drivers/gpu/drm/radeon/radeon_fence.c >>>>>> index 7733429..6da1535 100644 >>>>>> --- a/drivers/gpu/drm/radeon/radeon_fence.c >>>>>> +++ b/drivers/gpu/drm/radeon/radeon_fence.c >>>>>> @@ -386,9 +388,9 @@ int radeon_fence_driver_start_ring(struct >>>>>> radeon_device *rdev, int ring) >>>>>> rdev->fence_drv[ring].scratch_reg - >>>>>> rdev->scratch.reg_base; >>>>>> } >>>>>> - rdev->fence_drv[ring].cpu_addr =rdev->wb.wb[index/4]; >>>>>> + rdev->fence_drv[ring].cpu_addr =u64*)&rdev->wb.wb[index/4]; >>>>> Might want to ensure cpu_addr is 64 bit aligned, or there might be >>>>> trouble on some architectures. >>>>> >>>>> >>>>> With this change, Cayman cards will already use six scratch registers >>>>> for the rings. It won't be possible to extend this scheme for even one >>>>> additional ring, will it? >>>> >>>> That won't work anyway, since not all rings can deal with 64 bit fences, so >>>> we need to still use 32 bit signaling and extend them to 64 bit while >>>> processing the fence value. >>>> >>>> Already working on that. >>>> >>>> Christian. >>> This patch is fine with ring that can't emit directly 64bits, all you >>> have to do is fix the emit_fence callback to properly handle it and >>> then you have to fix the radeon_fence_read which can be move to a ring >>> specific callback. Anyway point is that patchset works and is fine on >>> current set of ring we have and it can work as easily for ring without >>> easy 64bits value emitting. So please explain further why those patch >>> can't work because as i just explained i don't see why. >>> >>> I have updated some v2 version of those patchset to handle the cayman >>> and newer possibly running out of scratch reg and i also fix the >>> alignment issue to be 64bits >> FWIW, we don't actually use scratch regs any more on r6xx+ (non-AGP at >> least), it's just memory writes so we could make the scratch pool >> bigger. >> >> Alex >> > That's what my v2 does, just drop scratch reg for cayman and newer. > > Cheers, > Jerome > I actually always wanted to change that in a way that scratch regs are only allocated if wb is really disabled, just never had time to do so (sigh).
Cheers, Christian.
