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Jérôme Pouiller
c86176d513
wfx_bh_request_tx() send HIF request asynchronously through bh_work().
Then the caller will run wfx_bh_poll_irq() to poll the answer.
However it useless to burn CPU cycles for the polling while the request
has yet been sent. Worse, wfx_bh_poll_irq() may get the CPU and prevent
wfx_bh_request_tx() to run. This problem has been observed on mono core
architecture.
This first exchange is correct:
kworker/u2:1-24 [000] .... : io_read32: CONTROL: 00003000
kworker/u2:1-24 [000] .... : io_read32: CONTROL: 00003000
kworker/u2:1-24 [000] .... : io_read32: CONTROL: 00003004
kworker/u2:1-24 [000] .... : io_read32: CONTROL: 00003004
kworker/0:1H-40 [000] .... : io_read: QUEUE: 08 00 09 0c 00 00 00 00 3a 7b 00 30 (12 bytes)
kworker/0:1H-40 [000] .... : piggyback: CONTROL: 00003000
kworker/0:1H-40 [000] .... : hif_recv: 0:2:CNF_CONFIGURATION: 00 00 00 00 (8 bytes)
kworker/0:1H-40 [000] .... : io_read32: CONFIG: 03010200
kworker/0:1H-40 [000] .... : bh_stats: IND/REQ/CNF: 0/ 0/ 1, REQ in progress: 0, WUP: release
... while the following is not:
kworker/u2:1-24 [000] .... : io_read32: CONTROL: 00003000
kworker/u2:1-24 [000] .... : io_read32: CONTROL: 00003000
kworker/u2:1-24 [000] .... : io_read32: CONTROL: 00003000
[...loop until timeout...]
wfx-sdio mmc0:0001:1: time out while polling control register
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20220225112405.355599-10-Jerome.Pouiller@silabs.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
``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.