On Thu, Feb 22, 2018 at 11:45 AM, Ben Crocker <bcrocker@xxxxxxxxxx> wrote: > I considered that, but I'm only equipped to test on a few cards--the ones > IBM is interested in. > So this Cedar-specific change fixes the problem on the FirePro 2270; the > other cards seem > perfectly capable of handling 40+ bit DMA addresses on the Power8 platform. Which other cards? Alex > > > On Thu, Feb 22, 2018 at 11:07 AM, Alex Deucher <alexdeucher@xxxxxxxxx> > wrote: >> >> On Thu, Feb 22, 2018 at 10:55 AM, Ben Crocker <bcrocker@xxxxxxxxxx> wrote: >> > Alex, Christian, et al. >> > >> > Thanks for your rapid response! >> > >> > I can certainly make the change PPC-only (#ifdef CONFIG_PPC64...) and I >> > think >> > that's the safest way to go right now. It makes the patch very specific >> > to >> > Cedar >> > on PowerPC64, so it doesn't break anything that may have come to depend >> > on >> > Russell's and Alistair's changes, and my timetable for getting a fix in >> > is >> > very short. >> >> If you want to go this route, you might just set need_dma32 >> unconditionally for PPC64. The bus interface hw is pretty much the >> same across all asics in this time period. >> >> Alex >> >> >> > >> > -- Ben >> > >> > >> > >> > On Thu, Feb 22, 2018 at 2:25 AM, Christian König >> > <ckoenig.leichtzumerken@xxxxxxxxx> wrote: >> >> >> >> Am 22.02.2018 um 03:05 schrieb Alex Deucher: >> >>> >> >>> On Wed, Feb 21, 2018 at 6:41 PM, Ben Crocker <bcrocker@xxxxxxxxxx> >> >>> wrote: >> >>>> >> >>>> In radeon_device_init, set the need_dma32 flag for Cedar chips >> >>>> (e.g. FirePro 2270). This fixes, or at least works around, a bug >> >>>> on PowerPC exposed by last year's commits >> >>>> >> >>>> 8e3f1b1d8255105f31556aacf8aeb6071b00d469 (Russell Currey) >> >>>> >> >>>> and >> >>>> >> >>>> 253fd51e2f533552ae35a0c661705da6c4842c1b (Alistair Popple) >> >>>> >> >>>> which enabled the 64-bit DMA iommu bypass. >> >>>> >> >>>> This caused the device to freeze, in some cases unrecoverably, and is >> >>>> the subject of several bug reports internal to Red Hat. >> >>> >> >>> Can we make this ppc only? 40 bit DMA works fine on x86. >> >> >> >> >> >> Yeah and at least when the dma_coherent allocator path is used it >> >> should >> >> work fine on PPC as well. >> >> >> >> So that is not really a driver bug, but a platform bug and we should >> >> think >> >> about reverting or at least disabling those two patches instead. >> >> >> >> Christian. >> >> >> >>> >> >>> Alex >> >>> >> >>>> Signed-off-by: Ben Crocker <bcrocker@xxxxxxxxxx> >> >>>> --- >> >>>> drivers/gpu/drm/radeon/radeon_device.c | 5 ++++- >> >>>> 1 file changed, 4 insertions(+), 1 deletion(-) >> >>>> >> >>>> diff --git a/drivers/gpu/drm/radeon/radeon_device.c >> >>>> b/drivers/gpu/drm/radeon/radeon_device.c >> >>>> index ffc10cadcf34..02538903830d 100644 >> >>>> --- a/drivers/gpu/drm/radeon/radeon_device.c >> >>>> +++ b/drivers/gpu/drm/radeon/radeon_device.c >> >>>> @@ -1395,7 +1395,10 @@ int radeon_device_init(struct radeon_device >> >>>> *rdev, >> >>>> if (rdev->flags & RADEON_IS_AGP) >> >>>> rdev->need_dma32 = true; >> >>>> if ((rdev->flags & RADEON_IS_PCI) && >> >>>> - (rdev->family <= CHIP_RS740)) >> >>>> + (rdev->family <= CHIP_RS740 || rdev->family == >> >>>> CHIP_CEDAR)) >> >>>> + rdev->need_dma32 = true; >> >>>> + if ((rdev->flags & RADEON_IS_PCIE) && >> >>>> + (rdev->family == CHIP_CEDAR)) >> >>>> rdev->need_dma32 = true; >> >>>> >> >>>> dma_bits = rdev->need_dma32 ? 32 : 40; >> >>>> -- >> >>>> 2.13.6 >> >>>> >> >>>> _______________________________________________ >> >>>> dri-devel mailing list >> >>>> dri-devel@xxxxxxxxxxxxxxxxxxxxx >> >>>> https://lists.freedesktop.org/mailman/listinfo/dri-devel >> >>> >> >>> _______________________________________________ >> >>> amd-gfx mailing list >> >>> amd-gfx@xxxxxxxxxxxxxxxxxxxxx >> >>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx >> >> >> >> >> > >> _______________________________________________ >> amd-gfx mailing list >> amd-gfx@xxxxxxxxxxxxxxxxxxxxx >> https://lists.freedesktop.org/mailman/listinfo/amd-gfx > > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
