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-rw-r--r--0003-mfd-intel-lpss-Use-devm_ioremap_uc-for-MMIO.patch48
1 files changed, 48 insertions, 0 deletions
diff --git a/0003-mfd-intel-lpss-Use-devm_ioremap_uc-for-MMIO.patch b/0003-mfd-intel-lpss-Use-devm_ioremap_uc-for-MMIO.patch
new file mode 100644
index 0000000..853d2b7
--- /dev/null
+++ b/0003-mfd-intel-lpss-Use-devm_ioremap_uc-for-MMIO.patch
@@ -0,0 +1,48 @@
+From 5408dcb0a652b76a5e190a68ce737a9a903cdfc0 Mon Sep 17 00:00:00 2001
+From: Tuowen Zhao <ztuowen@gmail.com>
+Date: Wed, 16 Oct 2019 15:06:29 -0600
+Subject: mfd: intel-lpss: Use devm_ioremap_uc for MMIO
+
+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>
+---
+ 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;
+--
+cgit v1.2.1-1-g437b
+