Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 35/50] mfd: intel-lpss: Use devm_ioremap_uc for MMIO | Date | Fri, 8 May 2020 14:35:41 +0200 |
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From: Tuowen Zhao <ztuowen@gmail.com>
commit a8ff78f7f773142eb8a8befe5a95dd6858ebd635 upstream.
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 Cc: <stable@vger.kernel.org> # v4.19+ Tested-by: AceLan Kao <acelan.kao@canonical.com> Signed-off-by: Tuowen Zhao <ztuowen@gmail.com> Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Roman Gilg <subdiff@gmail.com> Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/mfd/intel-lpss.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/mfd/intel-lpss.c +++ b/drivers/mfd/intel-lpss.c @@ -384,7 +384,7 @@ int intel_lpss_probe(struct device *dev, if (!lpss) return -ENOMEM; - lpss->priv = devm_ioremap(dev, info->mem->start + LPSS_PRIV_OFFSET, + lpss->priv = devm_ioremap_uc(dev, info->mem->start + LPSS_PRIV_OFFSET, LPSS_PRIV_SIZE); if (!lpss->priv) return -ENOMEM;
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