Messages in this thread Patch in this message | | | From | Tuowen Zhao <> | Subject | [PATCH v3 2/2] mfd: intel-lpss: use devm_ioremap_uc for MMIO | Date | Wed, 9 Oct 2019 21:03:35 -0600 |
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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.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> --- drivers/mfd/intel-lpss.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mfd/intel-lpss.c b/drivers/mfd/intel-lpss.c index bfe4ff337581..b0f0781a6b9c 100644 --- 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; -- 2.23.0
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