ee277704a4
[ Upstream commit 346f59d1e8ed0eed41c80e1acb657e484c308e6a ] Many devices with a single alternate setting do not have a Valid Alternate Setting Control and validation performed by validate_sample_rate_table_v2v3() doesn't work on them and is not really needed. So check the presense of control before sending altsetting validation requests. MOTU Microbook IIc is suffering the most without this check. It takes up to 40 seconds to bootup due to how slow it switches sampling rates: [ 2659.164824] usb 3-2: New USB device found, idVendor=07fd, idProduct=0004, bcdDevice= 0.60 [ 2659.164827] usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [ 2659.164829] usb 3-2: Product: MicroBook IIc [ 2659.164830] usb 3-2: Manufacturer: MOTU [ 2659.166204] usb 3-2: Found last interface = 3 [ 2679.322298] usb 3-2: No valid sample rate available for 1:1, assuming a firmware bug [ 2679.322306] usb 3-2: 1:1: add audio endpoint 0x3 [ 2679.322321] usb 3-2: Creating new data endpoint #3 [ 2679.322552] usb 3-2: 1:1 Set sample rate 96000, clock 1 [ 2684.362250] usb 3-2: 2:1: cannot get freq (v2/v3): err -110 [ 2694.444700] usb 3-2: No valid sample rate available for 2:1, assuming a firmware bug [ 2694.444707] usb 3-2: 2:1: add audio endpoint 0x84 [ 2694.444721] usb 3-2: Creating new data endpoint #84 [ 2699.482103] usb 3-2: 2:1 Set sample rate 96000, clock 1 Signed-off-by: Alexander Tsoy <alexander@tsoy.me> Link: https://lore.kernel.org/r/20240129121254.3454481-1-alexander@tsoy.me Signed-off-by: Takashi Iwai <tiwai@suse.de> 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.