| Is it better to enable SWIOTLB? Are there any advantages with SWIOTLB enabled?
— Christian Sent from my iPhone On 2017-11-27 01:17 PM, Tom St Denis wrote:On 27/11/17 07:02 AM, Michel Dänzer wrote:
On 2017-11-27 12:50 PM, Christian König wrote:
Am 27.11.2017 um 12:02 schrieb Michel Dänzer:
On 2017-11-24 05:09 PM, Michel Dänzer wrote:
On 2017-11-24 03:29 PM, Christian Zigotzky wrote:
Hi All,
I bisected today and the first bad commit is:
a4dec819c8bba6365eb893a4ca88db4dd1210110 (drm/ttm: Add helper
functions
to populate/map in one call (v2)) [1]
It can't really be that commit, since it just adds functions but
doesn't
hook them up anywhere. Presumably it's commit
f7871fd19389c5f64f625a4389675d0740f0dfe4 ("drm/radeon: use new TTM
populate/dma map helper functions") instead, which makes the radeon
driver rely on ttm_populate_and_map_pages, which is just a stub
returning -ENOMEM when neither CONFIG_SWIOTLB nor
CONFIG_INTEL_IOMMU is
enabled.
I can see two possible solutions:
1. Make ttm_populate_and_map_pages and ttm_unmap_and_unpopulate_pages
work without SWIOTLB / INTEL_IOMMU as well.
2. Make the drivers work without ttm_populate_and_map_pages and
ttm_unmap_and_unpopulate_pages again in that case.
Solution 1 would be preferable.
Which solution do you want to go for?
well, can somebody please explain to me why those patches actually
result in problems?
I thought I did above...
Commit f7871fd19389c5f64f625a4389675d0740f0dfe4 made the radeon driver
rely on ttm_populate_and_map_pages, which is implemented as:
static inline int ttm_populate_and_map_pages(struct device *dev,
struct ttm_dma_tt *tt)
{
return -ENOMEM;
}
when neither CONFIG_SWIOTLB nor CONFIG_INTEL_IOMMU is enabled.
Previously, the driver worked fine without either of those enabled.
I think the issue is why would you have both disabled [...]
Doesn't matter. The drivers worked with both disabled before, now theydon't. That's a regression.-- Earthling Michel Dänzer | http://www.amd.comLibre software enthusiast | Mesa and X developer
|
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