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Filename Latest commit message Latest commit date
Martin Fuzzey 772e5f29c9 dmaengine: imx-sdma: fix context cache
commit d288bddd8374e0a043ac9dde64a1ae6a09411d74 upstream.

There is a DMA problem with the serial ports on i.MX6.

When the following sequence is performed:

1) Open a port
2) Write some data
3) Close the port
4) Open a *different* port
5) Write some data
6) Close the port

The second write sends nothing and the second close hangs.
If the first close() is omitted it works.

Adding logs to the the UART driver shows that the DMA is being setup but
the callback is never invoked for the second write.

This used to work in 4.19.

Git bisect leads to:
	ad0d92d: "dmaengine: imx-sdma: refine to load context only once"

This commit adds a "context_loaded" flag used to avoid unnecessary context
setups.
However the flag is only reset in sdma_channel_terminate_work(),
which is only invoked in a worker triggered by sdma_terminate_all() IF
there is an active descriptor.

So, if no active descriptor remains when the channel is terminated, the
flag is not reset and, when the channel is later reused the old context
is used.

Fix the problem by always resetting the flag in sdma_free_chan_resources().

Cc: stable@vger.kernel.org
Signed-off-by: Martin Fuzzey <martin.fuzzey@flowbird.group>
Fixes: ad0d92d7ba ("dmaengine: imx-sdma: refine to load context only once")
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/1580305274-27274-1-git-send-email-martin.fuzzey@flowbird.group
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-12 13:00:23 +01:00
arch s390/mm: fix panic in gup_fast on large pud 2020-03-12 13:00:22 +01:00
block block, bfq: do not insert oom queue into position tree 2020-03-12 13:00:08 +01:00
certs
crypto crypto: rename sm3-256 to sm3 in hash_algo_name 2020-02-28 17:22:26 +01:00
Documentation netfilter: nf_flowtable: fix documentation 2020-03-05 16:43:51 +01:00
drivers dmaengine: imx-sdma: fix context cache 2020-03-12 13:00:23 +01:00
fs btrfs: fix RAID direct I/O reads with alternate csums 2020-03-12 13:00:20 +01:00
include mm, hotplug: fix page online with DEBUG_PAGEALLOC compiled but not enabled 2020-03-12 13:00:19 +01:00
init kbuild: remove header compile test 2020-03-05 16:43:47 +01:00
ipc Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" 2020-02-28 17:22:20 +01:00
kernel blktrace: fix dereference after null check 2020-03-12 13:00:10 +01:00
lib kbuild: move headers_check rule to usr/include/Makefile 2020-03-05 16:43:47 +01:00
LICENSES
mm mm, hotplug: fix page online with DEBUG_PAGEALLOC compiled but not enabled 2020-03-12 13:00:19 +01:00
net netfilter: nft_tunnel: no need to call htons() when dumping ports 2020-03-05 16:43:50 +01:00
samples samples/bpf: Set -fno-stack-protector when building BPF programs 2020-02-24 08:36:36 +01:00
scripts kbuild: move headers_check rule to usr/include/Makefile 2020-03-05 16:43:47 +01:00
security efi: Only print errors about failing to get certs if EFI vars are found 2020-03-12 13:00:14 +01:00
sound ALSA: hda/realtek - Enable the headset of ASUS B9450FA with ALC294 2020-03-12 13:00:18 +01:00
tools perf arm-spe: Fix endless record after being terminated 2020-03-12 13:00:22 +01:00
usr kbuild: fix 'No such file or directory' warning when cleaning 2020-03-12 13:00:09 +01:00
virt KVM: Check for a bad hva before dropping into the ghc slow path 2020-03-05 16:43:48 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: Update drm/i915 bug filing URL 2020-02-28 17:22:19 +01:00
Makefile Linux 5.4.24 2020-03-05 16:43:52 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.