3afc842e66
commit fe81f354841641c7f71163b84912b25c169ed8ec upstream.
Testing ohci functionality with qemu's pci-ohci emulation often results
in ohci interface stalls, resulting in hung task timeouts.
The problem is caused by lost interrupts between the emulation and the
Linux kernel code. Additional interrupts raised while the ohci interrupt
handler in Linux is running and before the handler clears the interrupt
status are not handled. The fix for a similar problem in ehci suggests
that the problem is likely caused by edge-triggered MSI interrupts. See
commit 0b60557230ad ("usb: ehci: Prevent missed ehci interrupts with
edge-triggered MSI") for details.
Ensure that the ohci interrupt code handles all pending interrupts before
returning to solve the problem.
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: stable@vger.kernel.org
Fixes: 306c54d0edb6 ("usb: hcd: Try MSI interrupts on PCI devices")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://lore.kernel.org/r/20240429154010.1507366-1-linux@roeck-us.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.