No description
  • C 96.8%
  • Assembly 0.9%
  • Rust 0.7%
  • Shell 0.6%
  • Python 0.5%
  • Other 0.3%
Find a file
Michal Pecio e63d217388 usb: xhci: Don't unchain link TRBs on quirky HCs
[ Upstream commit e6aec6d9f5 ]

Some old HCs ignore transfer ring link TRBs whose chain bit is unset.
This breaks endpoint operation and sometimes makes it execute other
ring's TDs, which may corrupt their buffers or cause unwanted device
action. We avoid this by chaining all link TRBs on affected rings.

Fix an omission which allows them to be unchained by cancelling TDs.

The patch was tested by reproducing this condition on an isochronous
endpoint (non-power-of-two TDs are sometimes split not to cross 64K)
and printing link TRBs in trb_to_noop() on good and buggy HCs.

Actual hardware malfunction is rare since it requires Missed Service
Error shortly before the unchained link TRB, at least on NEC and AMD.
I have never seen it after commit bb0ba4cb10 ("usb: xhci: Apply the
link chain quirk on NEC isoc endpoints"), but it's Russian roulette
and I can't test all affected hosts and workloads. Fairly often MSEs
happen after cancellation because the endpoint was stopped.

Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://patch.msgid.link/20251119142417.2820519-11-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2026-01-02 12:57:02 +01:00
arch
block
certs
crypto
Documentation
drivers
fs
include
init
io_uring
ipc
kernel
lib
LICENSES
mm
net
rust
samples
scripts
security
sound
tools
usr
virt
.clang-format
.clippy.toml
.cocciconfig
.editorconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
.pylintrc
.rustfmt.toml
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile
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 reStructuredText 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.