diff --git a/debian/changelog b/debian/changelog index 26ebcfc78..37ea72ca4 100644 --- a/debian/changelog +++ b/debian/changelog @@ -3,6 +3,8 @@ linux (3.16.7-ckt7-2) UNRELEASED; urgency=medium [ Ian Campbell ] * Initialise framebuffer console earlier. (Closes: #779935) * [xen] Enable Xen MCE log support. (Closes: #779698) + * [armhf] mvebu: do not register custom DMA operations when coherency is + disabled (Closes: #780858) -- Ian Campbell Wed, 18 Mar 2015 21:07:15 +0000 diff --git a/debian/patches/bugfix/arm/mvebu-do-not-register-custom-DMA-operations-when-coherency-is-disabled.patch b/debian/patches/bugfix/arm/mvebu-do-not-register-custom-DMA-operations-when-coherency-is-disabled.patch new file mode 100644 index 000000000..d5d7e5d46 --- /dev/null +++ b/debian/patches/bugfix/arm/mvebu-do-not-register-custom-DMA-operations-when-coherency-is-disabled.patch @@ -0,0 +1,57 @@ +From: Thomas Petazzoni +Date: Thu Mar 12 03:58:12 PDT 2015 +Subject: [PATCH 3.18-stable v2] ARM: mvebu: do not register custom DMA operations when coherency is disabled +Origin: http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/330108.html + +This patch is a partial backport of commit ef01c6c36bb8 ("ARM: mvebu: +remove Armada 375 Z1 workaround for I/O coherency"). This commit was +merged in v3.19, so kernel versions later than v3.19 are not affected +by the problem that this commit fixes. + +It does not make a lot of sense to backport this commit entirely, +since it is mainly removing some no longer useful code. However, this +commit is also making sure that the bus_register_notifier that +register the custom DMA operations that should be used for HW I/O +coherency does not get registered when said HW I/O coherency is not +enabled. + +This is particularly critical since we have decided to disable HW I/O +coherency completely in all kernels < 4.0, to be on the safe side, +while experimenting a new implementation of the HW I/O coherency in >= +4.0. + +Without this commit, kernels earlier than 3.18 have the custom DMA +operations normally used for HW I/O coherency registered (they don't +do cache maintenance operations), while HW I/O coherency is +disabled. It essentially causes every DMA transfer to transfer +garbage. + +The issue fixed by this commit was introduced by 5ab5afd8ba83 ("ARM: +mvebu: implement Armada 375 coherency workaround"), but it was not +visible until now since it didn't cause any problem when HW I/O +coherency is enabled. + +Signed-off-by: Thomas Petazzoni +Cc: v3.16..v3.18 +--- + arch/arm/mach-mvebu/coherency.c | 5 +++-- + 1 file changed, 3 insertions(+), 2 deletions(-) + +diff --git a/arch/arm/mach-mvebu/coherency.c b/arch/arm/mach-mvebu/coherency.c +index 2ffccd4..01efe13 100644 +--- a/arch/arm/mach-mvebu/coherency.c ++++ b/arch/arm/mach-mvebu/coherency.c +@@ -448,8 +448,9 @@ static int __init coherency_late_init(void) + armada_375_coherency_init_wa(); + } + +- bus_register_notifier(&platform_bus_type, +- &mvebu_hwcc_nb); ++ if (coherency_available()) ++ bus_register_notifier(&platform_bus_type, ++ &mvebu_hwcc_nb); + + return 0; + } +-- +2.1.0 \ No newline at end of file diff --git a/debian/patches/series b/debian/patches/series index 8da1afffd..f88e5c59f 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -65,6 +65,7 @@ bugfix/x86/acpi-video-add-disable_native_backlight-quirk-for-samsung-730u3e-740u bugfix/x86/acpi-video-add-disable_native_backlight-quirk-for-samsung-510r.patch bugfix/x86/acpi-video-disable-native-backlight-on-samsung-series-9.patch bugfix/x86/drm-i915-quietly-reject-attempts-to-create-non-pagealigned-stolen-objects.patch +bugfix/arm/mvebu-do-not-register-custom-DMA-operations-when-coherency-is-disabled.patch # Arch features features/mips/MIPS-Support-hard-limit-of-cpu-count-nr_cpu_ids.patch