musb-hdrc: "Vbus off, timeout 1100 msec" message does not belong in sysfs

musb-hdrc: "Vbus off, timeout 1100 msec" message does not belong in sysfs

[Pavel Machek]

On Thu 2015-07-09 23:39:22, Pavel Machek wrote:
> Hi!
> 
> sysfs should contain one value per file. This one has at least two,
> with nice english sentence as a bonus.
> 
> root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto#
> cat vbus
> Vbus off, timeout 1100 msec
> 
> :-(.

Plus, documentation for this is nowhere to be seen:

pavel at amd:/data/l/linux-n900$ grep -ri musb Documentation/ABI/
pavel at amd:/data/l/linux-n900$

..which is a shame, because it is not really clear how to use this
one:

root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto#
cat mode
b_idle
root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto#
echo a_suspend > mode
-bash: echo: write error: Invalid argument
root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto#
echo a > mode
-bash: echo: write error: Invalid argument
root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto#
echo a_host > mode
-bash: echo: write error: Invalid argument
root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto#
echo b_host > mode
-bash: echo: write error: Invalid argument
root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto#
echo a_idle > mode
-bash: echo: write error: Invalid argument
root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto#
echo b_wait_acon > mode
-bash: echo: write error: Invalid argument
root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto#


									Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

musb-hdrc: "Vbus off, timeout 1100 msec" message does not belong in sysfs

[Pali Rohár]

On Thursday 09 July 2015 23:46:10 Pavel Machek wrote:
> On Thu 2015-07-09 23:39:22, Pavel Machek wrote:
> > Hi!
> > 
> > sysfs should contain one value per file. This one has at least two,
> > with nice english sentence as a bonus.
> > 
> > root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/mu
> > sb-hdrc.0.auto# cat vbus
> > Vbus off, timeout 1100 msec
> > 
> > :-(.
> 
> Plus, documentation for this is nowhere to be seen:
> 
> pavel at amd:/data/l/linux-n900$ grep -ri musb Documentation/ABI/
> pavel at amd:/data/l/linux-n900$
> 
> ..which is a shame, because it is not really clear how to use this
> one:
> 
> root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb
> -hdrc.0.auto# cat mode
> b_idle
> root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb
> -hdrc.0.auto# echo a_suspend > mode
> -bash: echo: write error: Invalid argument
> root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb
> -hdrc.0.auto# echo a > mode
> -bash: echo: write error: Invalid argument
> root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb
> -hdrc.0.auto# echo a_host > mode
> -bash: echo: write error: Invalid argument
> root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb
> -hdrc.0.auto# echo b_host > mode
> -bash: echo: write error: Invalid argument
> root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb
> -hdrc.0.auto# echo a_idle > mode
> -bash: echo: write error: Invalid argument
> root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb
> -hdrc.0.auto# echo b_wait_acon > mode
> -bash: echo: write error: Invalid argument
> root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb
> -hdrc.0.auto#
> 
> 
> 									Pavel

Hi!

I remember that this file is used for switching between usb peripheral 
and host mode. But because n900 HW somehow broken, for usb host mode are 
needed couple of "hack" patches which workaround HW bugs... This is 
still not enough and "support" from userspace is needed for it too.

Kernel patches are part of Maemo kernel-power 2.6.28 version and with 
package usbmode http://maemo.org/packages/view/usbmode/ is it possible 
to enter usb host mode on n900 (and then connect e.g. usb stick).

And IIRC correct command is:

# echo host > mode
# echo peripheral > mode

-- 
Pali Roh?r
pali.rohar at gmail.com
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musb-hdrc: "Vbus off, timeout 1100 msec" message does not belong in sysfs

[Sebastian Andrzej Siewior]

On 07/09/2015 11:46 PM, Pavel Machek wrote:
> On Thu 2015-07-09 23:39:22, Pavel Machek wrote:
>> Hi!

Hi,

>>
>> sysfs should contain one value per file. This one has at least two,
>> with nice english sentence as a bonus.
>>
>> root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto#
>> cat vbus
>> Vbus off, timeout 1100 msec
>>
>> :-(.
> 
> Plus, documentation for this is nowhere to be seen:
> 
> pavel at amd:/data/l/linux-n900$ grep -ri musb Documentation/ABI/
> pavel at amd:/data/l/linux-n900$

that is a shame indeed. It is part of the driver since TUSB support was
merged via commit 550a7375f ("USB: Add MUSB and TUSB support") about 7
years ago.
The parameter expects the timeout values which is used to poll the port
for mode changes (host/device mode) since it can not be detected on its
own.
Felipe knows best if it is better to document it or remove it. I can't
remember that I needed it on am335x.

> 									Pavel
> 
Sebastian

musb-hdrc: "Vbus off, timeout 1100 msec" message does not belong in sysfs

[Felipe Balbi]

On Fri, Jul 10, 2015 at 09:17:39AM +0200, Sebastian Andrzej Siewior wrote:
> On 07/09/2015 11:46 PM, Pavel Machek wrote:
> > On Thu 2015-07-09 23:39:22, Pavel Machek wrote:
> >> Hi!
> 
> Hi,
> 
> >>
> >> sysfs should contain one value per file. This one has at least two,
> >> with nice english sentence as a bonus.
> >>
> >> root at n900:/sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto#
> >> cat vbus
> >> Vbus off, timeout 1100 msec
> >>
> >> :-(.
> > 
> > Plus, documentation for this is nowhere to be seen:
> > 
> > pavel at amd:/data/l/linux-n900$ grep -ri musb Documentation/ABI/
> > pavel at amd:/data/l/linux-n900$
> 
> that is a shame indeed. It is part of the driver since TUSB support was
> merged via commit 550a7375f ("USB: Add MUSB and TUSB support") about 7
> years ago.
> The parameter expects the timeout values which is used to poll the port
> for mode changes (host/device mode) since it can not be detected on its
> own.
> Felipe knows best if it is better to document it or remove it. I can't
> remember that I needed it on am335x.

N900's usersland relies on it, IIRC. But it could be that it was used
just for testing. I'm not entirely sure.

-- 
balbi
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