On Thu, 10 Oct 2019, Luis Chamberlain wrote: > On Wed, Oct 09, 2019 at 09:03:35PM -0600, Tuowen Zhao wrote: > > Some BIOS erroneously specifies write-combining BAR for intel-lpss-pci > > in MTRR. This will cause the system to hang during boot. If possible, > > this bug could be corrected with a firmware update. > > > > This patch use devm_ioremap_uc to overwrite/ignore the MTRR settings > > by forcing the use of strongly uncachable pages for intel-lpss. > > > > The BIOS bug is present on Dell XPS 13 7390 2-in-1: > > > > [ 0.001734] 5 base 4000000000 mask 6000000000 write-combining > > > > 4000000000-7fffffffff : PCI Bus 0000:00 > > 4000000000-400fffffff : 0000:00:02.0 (i915) > > 4010000000-4010000fff : 0000:00:15.0 (intel-lpss-pci) > > > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=203485 > > Tested-by: AceLan Kao <acelan....@canonical.com> > > Signed-off-by: Tuowen Zhao <ztuo...@gmail.com> > > Acked-by: Mika Westerberg <mika.westerb...@linux.intel.com> > > Acked-by: Andy Shevchenko <andriy.shevche...@linux.intel.com> > > I think you'll want to Cc stable for this, as well as the last patch. > LTS kernels with the ioremap_uc will be able to leverage the fix.
When you re-submit adding Stable, you can apply my: For my own reference: Acked-for-MFD-by: Lee Jones <lee.jo...@linaro.org> -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog
