6bf55f6b0e
commit 0543e4e8852ef5ff1809ae62f1ea963e2ab23b66 upstream.
Since commit ae8709b296d8 ("USB: core: Make do_proc_control() and
do_proc_bulk() killable") if a device has the USB_QUIRK_DELAY_CTRL_MSG
quirk set, it will temporarily block all other URBs (e.g. interrupts)
while sleeping due to a control.
This results in noticeable delays when, for example, a userspace usbfs
application is sending URB interrupts at a high rate to a keyboard and
simultaneously updates the lock indicators using controls. Interrupts
with direction set to IN are also affected by this, meaning that
delivery of HID reports (containing scancodes) to the usbfs application
is delayed as well.
This patch fixes the regression by calling msleep() while the device
mutex is unlocked, as was the case originally with usb_control_msg().
Fixes: ae8709b296d8 ("USB: core: Make do_proc_control() and do_proc_bulk() killable")
Cc: stable <stable@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Tasos Sahanidis <tasos@tasossah.com>
Link: https://lore.kernel.org/r/3e299e2a-13b9-ddff-7fee-6845e868bc06@tasossah.com
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
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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.