** Description changed:
[SRU Justification]
[Impact]
- On Artful kernels, X fails to start and a kernel splat is printed.
+ On Artful and Bionic kernels, X fails to start and a kernel splat is printed.
This is cbecause ea642c3216cb ("drm/ttm: add io_mem_pfn callback") is
incomplete: the hisilicon hibmc driver does not contain the callback and
so the kernel tries to execute code at NULL.
[Fix]
- There is a discussion and potential fix at
https://lists.freedesktop.org/archives/dri-devel/2017-November/159002.html The
fix hasn't landed yet and it looks like they're going to re-engineer the entire
section instead.
- Rather than wait for that and deal with the massive regression
- potential, the fix I have picked to submit is very very minimal and
- touches only hibmc.
+ Bionic: There is a generic fix in 4.16 at
+ c67fa6edc8b11afe22c88a23963170bf5f151acf. It is part of a series that
+ applies this generic fix and does a bunch of cleanups; we can safely
+ just pick up the generic fix.
+
+ Artful: Rather than a generic fix, I have submitted a very very minimal
+ fix that only touches hibmc.
[Regression Potential]
- Minimal - fix only touches hibmc driver. Tested on D05 board.
+ Artful: Minimal - fix only touches hibmc driver. Tested on D05 board.
+ Bionic: fix is to generic drm code, but is small and easily reviewable.
[Testcase]
Install patched kernel, try to start X. If it succeeds, the fix works. If
there's a kernel splat, the fix does not work.
[Notes]
- HiSilicon would really like this fix in Artful in such time so that when the
next 16.04 point release ships in February, the HWE kernel will work with Xorg.
+ Artful: HiSilicon would really like this fix in Artful in such time so that
when the next 16.04 point release ships, the HWE kernel will work with Xorg.
+
+ Bionic: no extra notes.
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https://bugs.launchpad.net/bugs/1738334
Title:
hisilicon hibmc regression due to ea642c3216cb ("drm/ttm: add
io_mem_pfn callback")
Status in Linux:
New
Status in linux package in Ubuntu:
Confirmed
Status in linux source package in Artful:
Fix Released
Bug description:
[SRU Justification]
[Impact]
On Artful and Bionic kernels, X fails to start and a kernel splat is printed.
This is cbecause ea642c3216cb ("drm/ttm: add io_mem_pfn callback") is
incomplete: the hisilicon hibmc driver does not contain the callback
and so the kernel tries to execute code at NULL.
[Fix]
Bionic: There is a generic fix in 4.16 at
c67fa6edc8b11afe22c88a23963170bf5f151acf. It is part of a series that
applies this generic fix and does a bunch of cleanups; we can safely
just pick up the generic fix.
Artful: Rather than a generic fix, I have submitted a very very
minimal fix that only touches hibmc.
[Regression Potential]
Artful: Minimal - fix only touches hibmc driver. Tested on D05 board.
Bionic: fix is to generic drm code, but is small and easily reviewable.
[Testcase]
Install patched kernel, try to start X. If it succeeds, the fix works. If
there's a kernel splat, the fix does not work.
[Notes]
Artful: HiSilicon would really like this fix in Artful in such time so that
when the next 16.04 point release ships, the HWE kernel will work with Xorg.
Bionic: no extra notes.
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