** Changed in: hwe-next
Status: New => Fix Released
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https://bugs.launchpad.net/bugs/1845584
Title:
intel-lpss driver conflicts with write-combining MTRR region
Status in HWE Next:
Fix Released
Status in linux package in Ubuntu:
Fix Released
Status in linux-oem package in Ubuntu:
Invalid
Status in linux source package in Bionic:
Fix Committed
Status in linux-oem source package in Bionic:
Fix Released
Status in linux source package in Disco:
Fix Committed
Status in linux-oem source package in Disco:
Fix Released
Status in linux source package in Eoan:
Fix Released
Status in linux-oem source package in Eoan:
Invalid
Status in linux source package in Focal:
In Progress
Status in linux-oem source package in Focal:
Invalid
Bug description:
[Impact]
The memory region intel-lpss-pci uses has been declared as
write-combining
[ 0.001728] 5 base 4000000000 mask 6000000000 write-combining
This leads to the system hangs up during booting up.
This is a BIOS issue, but there are some platforms on the market and
users are struggling on booting up the machines. So, we may have to
fix this in the kernel.
[Fix]
Tuowen Zhao([email protected])[1] provides a diff patch for intel-lpss
driver to claim to use un-catchable memory while calling
__devm_ioremap(), and it works well. But it didn't be accepted by
maintainer yet.
To avoid the potential impact on other machines, I add a quirk to list
the machines which has the write-combining area in MTRR which overlaps
with the address that intel-lpss uses, only the machines in the list
pass the DEVM_IOREMAP_UC to __devm_ioremap().
[Test]
Verified on Dell XPS 13 7390 2-in-1
[Regression Potential]
Low, without this patch, the machine even can't boot. And the quirk only for
specific machines, so the modification won't affect other machines.
1. https://bugzilla.kernel.org/show_bug.cgi?id=203485#c23
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