Re: [PATCH v3 06/12] spi: spi-fsl-dspi: Replace interruptible wait queue with a simple completion
From: Michael Walle
Date: Mon Mar 16 2020 - 09:25:06 EST
Am 2020-03-16 14:00, schrieb Vladimir Oltean:
On Mon, 16 Mar 2020 at 14:49, Mark Brown <broonie@xxxxxxxxxx> wrote:
On Mon, Mar 16, 2020 at 02:29:09PM +0200, Vladimir Oltean wrote:
> Correct, the real problem is that I forgot to add a Fixes: tag for
> patch 5. I'll do that now.
OK. The series otherwise looked fine but I'll wait for testing.
Michael, if there's issues remaining it might be good to get some
Tested-bys for the patches prior to whatever's broken so we can get
those fixes in (but obviously verifying that is work so only if you
have time).
I'm just about to test it. While my former "cat /dev/mtdN > /dev/null"
is working. I had the impression that it was slower, so I tried to test
it with dd now and a known chunk size.. only to find out that it is
still not working:
# dmesg|grep spi
[ 1.894891] spi-nor spi1.0: w25q128fw (16384 Kbytes)
..
# time cat /dev/mtd0 > /dev/null
real 0m 30.73s
user 0m 0.00s
sys 0m 1.02s
# dd if=/dev/mtd0 of=/dev/null bs=64
262144+0 records in
262144+0 records out
# dd if=/dev/mtd0 of=/dev/null bs=64
262144+0 records in
262144+0 records out
# dd if=/dev/mtd0 of=/dev/null bs=64
dd: /dev/mtd0: Input/output error
I also wanted to test how it behaves if there are multiple processes
access the /dev/mtdN device. I haven't found the time to dig into
the call chain if see if there is any locking. Because what happens
if transfer_one_message() is called twice at the same time from two
different processes?
This time I verified with a protocol analyzer all transfer lengths
from 1 all the way to 256, with this script:
#!/bin/bash
buf=''
for i in $(seq 0 255); do
 buf="${buf}\x$(printf '%02x' ${i})"
 spidev_test --device /dev/spidev2.0 --bpw 8 --cpha --speed
5000000 -p "${buf}"
done
It looked fine as far as I could tell, and also the problems
surrounding Ctrl-C are no longer present. Nonetheless it would be good
if Michael could confirm, but I know that he's very busy too so it's
understandable if he can no longer spend time on this.
I'm working on it ;)
-michael