Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Fri, 7 Jan 2022 18:08:45 +0100 | Subject | Re: [PATCH v6 1/1] gpio: add sloppy logic analyzer using polling |
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Hi Wolfram,
On Wed, Dec 22, 2021 at 1:58 PM Wolfram Sang <wsa+renesas@sang-engineering.com> wrote: > > > Yes, the search engines helped[1]. I run a minimal system, so when I > > > mount cpusets, it will actually mount cgroups with a default mount > > > option of "noprefix". But you likely run a rootfs with cgroups already, > > > so it gets mounted directly without "noprefix". Then, when the logic > > > analyzer tries to mount again, the implied default "noprefix" is > > > discarded. > > > > Yeah, systemd on Debian has it mounted. > > So, the proper solution is to use/mount 'cgroups2' instead of 'cpuset'. > But this needs more thinking and testing and, thus, another revision. > Dunno if I can make it this year, so I am probably going to miss the > next merge window after all :( > > Geert, if you still want to test the PFC patch I sent, then this patch > for the script should get you going:
Thank you, much better!
With this I get:
1# gpio-sloppy-logic-analyzer -s 1500000 -t 1H+2F -d 15000 Auto-Isolating CPU1 Setting up 'i2c2-analyzer': 22500 samples at 1500000Hz with 1H+2F trigger using CPU1 1# echo: write error: Numerical result out of range Capture error! Check kernel log
kernel log has:
gpio-sloppy-logic-analyzer i2c2-analyzer: couldn't read GPIOs: -34
with debug code:
priv->delay_ns = 666 priv->acq_delay = 2342
Whoops, R-Car M2-W GPIO is too slow (clocked at 10 MHz, compared to 66 MHz on R-Car H3 ES2.0)?
Retry with slower speed, until it works:
1# gpio-sloppy-logic-analyzer -s 300000 -t 1H+2F -d 15000 Setting up 'i2c2-analyzer': 4500 samples at 300000Hz with 1H+2F trigger using CPU1 2# i2cdetect -y 2 1# cp: cannot stat '/sys/kernel/debug/gpio-sloppy-logic-analyzer/i2c2-analyzer/sample_data': No such file or directory
And the sample_data file is indeed missing.
After reboot, everything works fine, and I can no longer reproduce the missing file issue above, even when repeating the same steps. The resulting data file can be viewed with pulseview, and I can see SCL and SDA activity. Nice!
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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