[OpenOCD-devel] HIDAPI backend?

[Renaud C.]

Is there any reasons to prefer the hidraw backend versus the libusb
concerning hidapi? I've noticed that Ubuntu is shipping openocd with the
hidraw backend.

I've found that using the libusb backend, my CMSIS-DAP adapter is not
detected during the hid_enumerate() :

https://github.com/gnuarmeclipse/openocd/issues/12

Just trying to get some arguments to advocate for enforcing the hidraw
backend on the gnuarmeclipse build.

[Paul Fertser]

Hello,

Is there any reasons to prefer the hidraw backend versus the libusb concerning
hidapi? I've noticed that Ubuntu is shipping openocd with the hidraw backend. 
I've found that using the libusb backend, my CMSIS-DAP adapter is not detected

I've tested OpenOCD with hidapi-libusb on OpenWrt and it was able to
detect my adapter nicely. Can you please make sure it's not a
permissions issue? I'd rather prefer to make libusb backend work or at
least to fully understand its limitations.

[Renaud C.]

Yes, I'm 100% sure this is not a permission issue as stated in the
gnuarmeclipse issue:

https://github.com/gnuarmeclipse/openocd/issues/12

I did some debug, and the `hid_enumerate()` doesn't returns that adapter
when using the libusb backend. Switching to the hidraw backend fixed it. I
didn't noticed anything wrong on the build script:

https://github.com/gnuarmeclipse/build-scripts/blob/master/scripts/build-openocd.sh

Post by Paul Fertser
Hello,

Post by Renaud C.
Is there any reasons to prefer the hidraw backend versus the libusb

concerning

Post by Renaud C.
hidapi? I've noticed that Ubuntu is shipping openocd with the hidraw

backend.

Post by Renaud C.
I've found that using the libusb backend, my CMSIS-DAP adapter is not

detected
I've tested OpenOCD with hidapi-libusb on OpenWrt and it was able to
detect my adapter nicely. Can you please make sure it's not a
permissions issue? I'd rather prefer to make libusb backend work or at
least to fully understand its limitations.
--
Be free, use free (http://www.gnu.org/philosophy/free-sw.html) software!

[Paul Fertser]

Yes, I'm 100% sure this is not a permission issue as stated in the gnuarmeclipse
[1]https://github.com/gnuarmeclipse/openocd/issues/12
I did some debug, and the `hid_enumerate()` doesn't returns that adapter when
using the libusb backend. Switching to the hidraw backend fixed it. I didn't

Can you please provide strace log for the libusb backend? And HIDAPI
version. I can try to reproduce on my system here.

[Renaud Cerrato]

Not sure you received my previous email with the attachments?

Sure, here it is (launched with sudo), along with the lsusb output. My
adapter is on /dev/bus/usb/003/062 - but we can see that there's no
SYS_OPEN to that device which confirms my `hid_enumerate()` observations.
hidapi is the 0.7.0

Post by Renaud C.

Post by Renaud C.
Yes, I'm 100% sure this is not a permission issue as stated in the

gnuarmeclipse

Post by Renaud C.
[1]https://github.com/gnuarmeclipse/openocd/issues/12
I did some debug, and the `hid_enumerate()` doesn't returns that

adapter when

Post by Renaud C.
using the libusb backend. Switching to the hidraw backend fixed it. I

didn't
Can you please provide strace log for the libusb backend? And HIDAPI
version. I can try to reproduce on my system here.
--
Be free, use free (http://www.gnu.org/philosophy/free-sw.html) software!

[Renaud C.]

It looks like email with attachments are filtered out, so here's a copy
using pastebins. My adapter is on /dev/bus/usb/003/062 - but we can see
that there's no SYS_OPEN to that device which confirms my `hid_enumerate()`
observations:

https://pastebin.com/af5j4JtR
https://pastebin.com/RVkN003K

The hidapi version is the 0.7.0

Post by Renaud Cerrato
Not sure you received my previous email with the attachments?

Sure, here it is (launched with sudo), along with the lsusb output. My
adapter is on /dev/bus/usb/003/062 - but we can see that there's no
SYS_OPEN to that device which confirms my `hid_enumerate()` observations.
hidapi is the 0.7.0

Post by Renaud C.

Post by Renaud C.
Yes, I'm 100% sure this is not a permission issue as stated in the

gnuarmeclipse

Post by Renaud C.
[1]https://github.com/gnuarmeclipse/openocd/issues/12
I did some debug, and the `hid_enumerate()` doesn't returns that

adapter when

Post by Renaud C.
using the libusb backend. Switching to the hidraw backend fixed it. I

didn't
Can you please provide strace log for the libusb backend? And HIDAPI
version. I can try to reproduce on my system here.
--
Be free, use free (http://www.gnu.org/philosophy/free-sw.html) software!

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[Paul Fertser]

The hidapi version is the 0.7.0  

Oh my, can you please recheck with a recent version? I was testing
with 0.8.0-rc1. That 0.7.0 is really old.

[Paul Fertser]

Post by Paul Fertser

The hidapi version is the 0.7.0  

Oh my, can you please recheck with a recent version? I was testing
with 0.8.0-rc1. That 0.7.0 is really old.

https://github.com/signal11/hidapi/commit/a991328721b3b39cbc90f562b87df0bb1eeaf5c4
and
https://github.com/signal11/hidapi/commit/ec24f931007d75e061d26d6f9705790913f72fa0
might make all the difference in this case.

[Renaud C.]

Thanks Paul! Indeed, compiling against 0.8.0-rc1 made it... The
gnuarmeclipse build is using the 0.7.0 - I'm now able to fix their build
script!

Post by Paul Fertser

Post by Paul Fertser

Post by Renaud C.
The hidapi version is the 0.7.0

Oh my, can you please recheck with a recent version? I was testing
with 0.8.0-rc1. That 0.7.0 is really old.

https://github.com/signal11/hidapi/commit/a991328721b3b39cbc90f562b87df0bb1eeaf5c4
and
https://github.com/signal11/hidapi/commit/ec24f931007d75e061d26d6f9705790913f72fa0
might make all the difference in this case.
--
Be free, use free (http://www.gnu.org/philosophy/free-sw.html) software!

[Paul Fertser]

Thanks Paul! Indeed, compiling against 0.8.0-rc1 made it... The gnuarmeclipse
build is using the 0.7.0 - I'm now able to fix their build script!

Thanks for taking care of that! Hope to see you contributing to
OpenOCD as well one day ;)

[Liviu Ionescu]

... arguments to advocate for enforcing the hidraw backend on the gnuarmeclipse build.

please try the pre-release and let me know if it works:

https://github.com/gnuarmeclipse/openocd/releases/tag/gae-0.10.0-20170418


regards,

Liviu