Re: N900 will not allow USB OTG!
 

because some functions of kernel seems to be in place the single problem i see is vbus power management in host mode as i see host mode depend on this
on N900 vbus power management is broken because it use another asic OUTSIDE tusb6010 for which driver is not written.
on N810 this driver work so somebody must check with a patched driver ( with removed sections of vbus power ) if any device can work without vbus.
after that we can hope n900 will do the same
vbus will and can be a future option in driver / selection mode software
few weeks ago ( beginning of march ) i tried to inject vbus & session_valid on phy asic http://talk.maemo.org/showpost.php?p...&postcount=619 ( i will post a picture with test board )
i never believe the driver and HNP can be so grossly as manual removal of device from pc
i try the same thing as egoshin ( conect / disconect from a hub ) . http://talk.maemo.org/showpost.php?p...&postcount=624 .
tight usb timings blinded me .i have no success because i did not stop ( nasty word here ) bme

Re: N900 will not allow USB OTG!
 

Applied the patches (they only seem to add a kernel message when echoing host), kernel built and flashed.
Raised power output to 5V using joerg_rw's command.
However I still can't get it to work, the flash drive gets rejected.

Re: N900 will not allow USB OTG!
 

please have a close look to
http://mxr.maemo.org/fremantle/sourc...sb/musb_core.c
145 static inline int musb_verify_charger(void __iomem *addr)
ff
207

for seemingly working handling of the pullup/pulldown Rs (the MAIN most IMPORTANT config in PHY for hostmode)

Re: N900 will not allow USB OTG!
 

please see
61 * HP's USB bus-powered keyboard has only one configuration
ff
in http://mxr.maemo.org/fremantle/sourc...core/generic.c

[edit]
ok, seems we killed that issue by patching out a few rather useless checks in kernel. Probably MohammadAG will come up with a small and dirty patch eventually. No big thing though. Still the fake hostmode by tricking OTG statemachine, I.E needs laptop to simulate the yet missing switch of PHY to host config (2 pulldowns)

Re: N900 will not allow USB OTG!
 

guys, I have some news about bme's i2c communication with bq24150.
Be aware that this is ALL communication to bq24150 through the kernel. Not necessarily only by BME.

initialisation (contains some nonsense IMHO):
every 15s:
nothing too special, yet. But the printk's can be usefull when trying to find out how BME destroys VBUS, etc…

The diff for my printk's are attached.

Re: N900 will not allow USB OTG!
 

those messages are obtained with high power charger attached , right ?
so nothing special , bme reset 32 s timer 4 times per minute . too often i think but in charge mode any battery savings is nonsense.
bme don't destroy vbus , simply bme have no idea ( and code ) about vbus and host mode status.
code is written only for charging mode not charge or boost vbus

Re: N900 will not allow USB OTG!
 

try with a minimum 100 uF capacitor on vbus to avoid vbus drop ( early host specs don't throw with tomato )
681 if (int_usb & MUSB_INTR_VBUSERROR) {
682 int ignore = 0;
683
684 /* During connection as an A-Device, we may see a short
685 * current spikes causing voltage drop, because of cable
686 * and peripheral capacitance combined with vbus draw.
687 * (So: less common with truly self-powered devices, where
688 * vbus doesn't act like a power supply.)
689 *
690 * Such spikes are short; usually less than ~500 usec, max
691 * of ~2 msec. That is, they're not sustained overcurrent
692 * errors, though they're reported using VBUSERROR irqs.
693 *
694 * Workarounds: (a) hardware: use self powered devices.
695 * (b) software: ignore non-repeated VBUS errors.
696 *
697 * REVISIT: do delays from lots of DEBUG_KERNEL checks
698 * make trouble here, keeping VBUS < 4.4V ?
699 */
700 switch (musb->xceiv->state) {
701 case OTG_STATE_A_HOST:
702 /* recovery is dicey once we've gotten past the
703 * initial stages of enumeration, but if VBUS
704 * stayed ok at the other end of the link, and
705 * another reset is due (at least for high speed,
706 * to redo the chirp etc), it might work OK...
707 */

Re: N900 will not allow USB OTG!
 

We might want to operate hostmode without burning battery for VBUS boost, by using an externally powered hub.

Yeah we want to give our baby more energy, not take energy from it.


04-26-10 , 01:47 PM
Posts: 82 | Thanked: 9 times | Joined on Nov 2009 @ leicester UK

Report This | #1
Someone on one of the forums mentioned that the 'Memorex Travellink' could be used to transfer files from the n900 to a USB memory stick so I bought one.

Needless to say it did not work first time, but I thought it was still worth it because I could read and copy the SD card with it, so it would still be usable when I start travelling later on in the year.

Somebody posted an app to mount an exterior partition, so I downloaded it, plugged a USB stick into the Travellink and the n900 USB link 'coz I thought I could mount the stick with the downloaded app.

Much to my pleasant surprise, the Travellink was able to see files on my n900 and transfer them to my USB memory stick without the use of a PC or laptop, also it not did not need the mounter wizard.

What might have happened the first time is, I tried to do it without a fully charged battery, this time I tried with a fully charged battery, the perfect accessory for the traveller who wants to shoot lots of videos and store them on the road without carrying lots of kit.

The Travellink runs on three AA batteries, which I would imagine can be bought all over the planet.

Re: N900 will not allow USB OTG!
 

Compiled a kernel that works (finally! - thanks to joerg_rw for pointing out how to stop any power limits - my flash apparently needs more power).
I'll post a patch shortly.

I also got an HDD working, using the laptop as a power source, and without any "real" hub in between (using a Y cable though).

The echo host > ... part is redundant and doesn't do anything, so it can be left out.
Not sure about the patches, but it seems they only add messages to the kernel messages. Also I had to edit the .config file directly not the one in arch/arm/configs, since that didn't change anything (thanks to javispedro for that one)

Making the drive appear in file manager is **** easy, just create a directory in /media and mount the drive/flash to it.

http://i47.tinypic.com/wmkll4.jpg

http://i46.tinypic.com/m82rmq.jpg

http://i48.tinypic.com/1zxbq6g.jpg

Re: N900 will not allow USB OTG!
 

It is a CPU frequency boost on any event from your WD HD.