0e4528cdba
[ Upstream commit 5727043c73fdfe04597971b5f3f4850d879c1f4f ] The AMD Starship USB 3.0 host controller advertises Function Level Reset support, but it apparently doesn't work. Add a quirk to prevent use of FLR on this device. Without this quirk, when attempting to assign (pass through) an AMD Starship USB 3.0 host controller to a guest OS, the system becomes increasingly unresponsive over the course of several minutes, eventually requiring a hard reset. Shortly after attempting to start the guest, I see these messages: vfio-pci 0000:05:00.3: not ready 1023ms after FLR; waiting vfio-pci 0000:05:00.3: not ready 2047ms after FLR; waiting vfio-pci 0000:05:00.3: not ready 4095ms after FLR; waiting vfio-pci 0000:05:00.3: not ready 8191ms after FLR; waiting And then eventually: vfio-pci 0000:05:00.3: not ready 65535ms after FLR; giving up INFO: NMI handler (perf_event_nmi_handler) took too long to run: 0.000 msecs perf: interrupt took too long (642744 > 2500), lowering kernel.perf_event_max_sample_rate to 1000 INFO: NMI handler (perf_event_nmi_handler) took too long to run: 82.270 msecs INFO: NMI handler (perf_event_nmi_handler) took too long to run: 680.608 msecs INFO: NMI handler (perf_event_nmi_handler) took too long to run: 100.952 msecs ... watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [qemu-system-x86:7487] Tested on a Micro-Star International Co., Ltd. MS-7C59/Creator TRX40 motherboard with an AMD Ryzen Threadripper 3970X. Link: https://lore.kernel.org/r/20200524003529.598434ff@f31-4.lan Signed-off-by: Kevin Buettner <kevinb@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.