| Message ID | 20221201232100.221606-1-marex@denx.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RFC] drm/etnaviv: Disable softpin | expand |
Am Freitag, dem 02.12.2022 um 00:21 +0100 schrieb Marek Vasut: > Currently softpin suffers from assorted race conditions exposed by newer > versions of mesa 22.2.y and 22.3.y . Those races are difficult to fix in > older kernel versions due to massive amount of backports necessary to do > so. Disable softpin by default until Linux 6.1.y is out, which contains > the necessary fixes to make softpin work reliably. > Sorry, but that's a NACK. The userspace driver depends on softpin for GPUs with texture descriptors, so this introduces a hard functional regression for those GPUs. I.e. they would go from "require race fixes that are already on the way to upstream" to not working at all. Regards, Lucas > Fixes: 088880ddc0b20 ("drm/etnaviv: implement softpin") > Signed-off-by: Marek Vasut <marex@denx.de> > --- > Cc: Christian Gmeiner <christian.gmeiner@gmail.com> > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: David Airlie <airlied@linux.ie> > Cc: Lucas Stach <l.stach@pengutronix.de> > Cc: Russell King <linux+etnaviv@armlinux.org.uk> > Cc: etnaviv@lists.freedesktop.org > To: dri-devel@lists.freedesktop.org > --- > drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c > index 51320eeebfcff..326c9696cccea 100644 > --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c > +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c > @@ -146,10 +146,7 @@ int etnaviv_gpu_get_param(struct etnaviv_gpu *gpu, u32 param, u64 *value) > break; > > case ETNAVIV_PARAM_SOFTPIN_START_ADDR: > - if (priv->mmu_global->version == ETNAVIV_IOMMU_V2) > - *value = ETNAVIV_SOFTPIN_START_ADDRESS; > - else > - *value = ~0ULL; > + *value = ~0ULL; > break; > > case ETNAVIV_PARAM_GPU_PRODUCT_ID:
On 12/2/22 09:59, Lucas Stach wrote: > Am Freitag, dem 02.12.2022 um 00:21 +0100 schrieb Marek Vasut: >> Currently softpin suffers from assorted race conditions exposed by newer >> versions of mesa 22.2.y and 22.3.y . Those races are difficult to fix in >> older kernel versions due to massive amount of backports necessary to do >> so. Disable softpin by default until Linux 6.1.y is out, which contains >> the necessary fixes to make softpin work reliably. >> > Sorry, but that's a NACK. The userspace driver depends on softpin for > GPUs with texture descriptors, so this introduces a hard functional > regression for those GPUs. I.e. they would go from "require race fixes > that are already on the way to upstream" to not working at all. I expected that NAK. But then, what options do we have here, except for a massive convoluted backport, which might bring bugs of its own ?
Am Freitag, dem 02.12.2022 um 11:20 +0100 schrieb Marek Vasut: > On 12/2/22 09:59, Lucas Stach wrote: > > Am Freitag, dem 02.12.2022 um 00:21 +0100 schrieb Marek Vasut: > > > Currently softpin suffers from assorted race conditions exposed by newer > > > versions of mesa 22.2.y and 22.3.y . Those races are difficult to fix in > > > older kernel versions due to massive amount of backports necessary to do > > > so. Disable softpin by default until Linux 6.1.y is out, which contains > > > the necessary fixes to make softpin work reliably. > > > > > Sorry, but that's a NACK. The userspace driver depends on softpin for > > GPUs with texture descriptors, so this introduces a hard functional > > regression for those GPUs. I.e. they would go from "require race fixes > > that are already on the way to upstream" to not working at all. > > I expected that NAK. > > But then, what options do we have here, except for a massive convoluted > backport, which might bring bugs of its own ? There is no other option. The kernel driver in the LTS releases does have a buggy softpin implementation. If someone cares about being able to keep their system on the LTS kernel, then that someone either needs to carry out the backports of the fixes with the necessary diligence or sponsor someone to do it. Regards, Lucas
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c index 51320eeebfcff..326c9696cccea 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c @@ -146,10 +146,7 @@ int etnaviv_gpu_get_param(struct etnaviv_gpu *gpu, u32 param, u64 *value) break; case ETNAVIV_PARAM_SOFTPIN_START_ADDR: - if (priv->mmu_global->version == ETNAVIV_IOMMU_V2) - *value = ETNAVIV_SOFTPIN_START_ADDRESS; - else - *value = ~0ULL; + *value = ~0ULL; break; case ETNAVIV_PARAM_GPU_PRODUCT_ID:
Currently softpin suffers from assorted race conditions exposed by newer versions of mesa 22.2.y and 22.3.y . Those races are difficult to fix in older kernel versions due to massive amount of backports necessary to do so. Disable softpin by default until Linux 6.1.y is out, which contains the necessary fixes to make softpin work reliably. Fixes: 088880ddc0b20 ("drm/etnaviv: implement softpin") Signed-off-by: Marek Vasut <marex@denx.de> --- Cc: Christian Gmeiner <christian.gmeiner@gmail.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: David Airlie <airlied@linux.ie> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Russell King <linux+etnaviv@armlinux.org.uk> Cc: etnaviv@lists.freedesktop.org To: dri-devel@lists.freedesktop.org --- drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)