On 8/17/2023 10:34 AM, Tim Hardisty wrote:
I have concluded that CDC/ACM will NOT play alongside SYSLOG - most
likely on the SAMA5D2 device, or possibly just on my board for some
reason.
Whatever I choose as the SYSLOG output (/dev/ttyS0, ttyS1, ttyFC0 and
ttyFC1 all of which are working fine, or even /dev/null) it just ends
up garbling received data from the USB.
I have left CONFIG_CDCACM_NRDREQ=1, disabled SYSLOG and can move
forward as this is only needed for the board test jig, so I don't need
a TTL->USB converter cable to see output.
Can return to it if anyone has any ideas but, if not, will log both as
issues for someone to pick up at some point in the future, maybe.
On 17/08/2023 16:06, Tim Hardisty wrote:
OK...progress.
CDC/ACM console behaves like this if CONFIG_CDCACM_NRDREQS is left at
the default 4. It needs a given keyboard key to be pressed 4 times to
work, and/or garbles the text sent. I also found that usbserial
example app misbehaves in the same way - I thought it was working
since random characters were being pressed by me to test it...and
received as garbled random characters and I didn't notice.
If set to 1 it works. I do not know why this is.
If this is a bug not some configuration error/mismatch I've not
spotted then I will raise it as an issue.
But it doesn't play nicely with syslog...I'm investigating that now.
Certainly you cannot use the console device for syslog because it there
is no console device when you use USB for the console output.
Non-console TTYs are not available at power up. Only the console serial
device (if there is one) is initialized in that case. They do become
available later, but after syslog is already been initialized. So there
may be some initialization issue in the way you use it.
I think there is an option to force late syslog initialization, but I
can't remember now (and this has probably been redesigned since I wrote
it anyway).
When I use a USB console, I normally output syslog to a circular buffer
(I forget all of the Kconfig options, but they should not be to hard to
find). Then I enable the NSH dmesg command. That will dump the output
of the syslog data from the circular buffer to the USB console, clearing
the buffer. Since buffering is available immediately after power up, no
boot-up data is lost. You just have to remember to enter the dmesg NSH
command periodically. You can do that with an NSH script running in the
background.
