mirror of
https://github.com/torvalds/linux.git
synced 2024-12-26 12:52:30 +00:00
c4d69da167
Running igt, I was encountering the invalid TLB bug on my 845g, despite that it was using the CS workaround. Examining the w/a buffer in the error state, showed that the copy from the user batch into the workaround itself was suffering from the invalid TLB bug (the first cacheline was broken with the first two words reversed). Time to try a fresh approach. This extends the workaround to write into each page of our scratch buffer in order to overflow the TLB and evict the invalid entries. This could be refined to only do so after we update the GTT, but for simplicity, we do it before each batch. I suspect this supersedes our current workaround, but for safety keep doing both. v2: The magic number shall be 2. This doesn't conclusively prove that it is the mythical TLB bug we've been trying to workaround for so long, that it requires touching a number of pages to prevent the corruption indicates to me that it is TLB related, but the corruption (the reversed cacheline) is more subtle than a TLB bug, where we would expect it to read the wrong page entirely. Oh well, it prevents a reliable hang for me and so probably for others as well. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: stable@vger.kernel.org Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Jani Nikula <jani.nikula@intel.com> |
||
|---|---|---|
| .. | ||
| drm | ||
| host1x | ||
| ipu-v3 | ||
| vga | ||
| Makefile | ||