Possible Hijack Bug

Because I needed to file taxi a large non-music file, I finally installed Hijack V.340 in my player. I think I might have been the last non-Hijack user in the known universe.

It did its job, allowed me to taxi the file, but I have had to remove Hijack and go back to the stock kernal.

The problem? With Hijack installed, about once out of every three or four times I booted the player in the car, it would start up in A/C mode instead of D/C mode. No fader (which I don't use anyway) but also no player shut-down when turning off the ignition. The "Force A/C-D/C Mode" setting was definitely set to "Normal".

The player works perfectly in every regard with the stock kernal, both in-car and plugged into A/C.

tanstaafl.

And may I interject here with a few pieces of information:

1. I walked Doug through every related diagnostic step known to me, starting with the assumption that he really did have a bad AC sensor switch and that the installation of Hijack was merely a coincidence. So please read his description with that knowledge in mind.

2. I seem to recall at least one other person reporting a similar problem on this BBS: After upgrading the software and installing Hijack, they got the "sometimes boots in AC mode" problem, and I also told them that it was only a coincidence and that there's no way Hijack could be accidentally putting the player into AC mode.

3. I still acknowledge that this could be just another coincidence with an intermittent AC sensor switch. But it's starting to look real suspicious now.

4. If, after reinstalling the stock Kernel, Doug gets an AC-mode boot in his car, I hope he will come here and let us know.

What's on the serial port in the car?

I knew about the possibility that it might be something connected to the serial port confusing Hijack and making it go into its "Mark's Home Dock" mode, but Doug said he had nothing connected to the in-car serial port. At least that's what I recall... I'll let Doug answer definitively.

Doug said he had nothing connected to the in-car serial port.

Maybe he should have. I can't remember much about serial ports now, but maybe it's "floating" and causing noise and spurious data. If it was plugged into something or you just pull the data pins low (or was it high?) it might stop generating noise.

Or I could be talking out of my hat.

Interesting concept.

In any case, if noise on the serial wires is what causes Hijack to accidentally enter AC mode, then I'd consider that a Hijack bug. Since the default way of installing the player is to have nothing connected to those wires.

I have an idea...

Doug... If Mark compiled you a special Hijack that didn't do the dock detection, would you be willing to install it and test it for him?

Mark... If Doug confirmed that the non-dock-detecting Hijack solved his problem, then would you be interested in using up a flash bit for a "Detect MLord Dock (Enabled/Disabled)" option?

Tony: If, after reinstalling the stock Kernel, Doug gets an AC-mode boot in his car, I hope he will come here and let us know.


My bootup (with the stock kernal) works perfectly: in-car it boots to DC mode (with fader, without default visuals, etc.) 100.0% of the time. On my desk, it boots to AC mode (without fader, with visuals, etc.) 100.0% of the time. Nothing intermittant.

Mark: What's on the serial port in the car?


Nothing. It is a pretty basic (but very high sound quality) installation: Just the empeg and a Clarion CD player feeding a Sony XA-39 switch, into two amplifiers and a dozen speakers on 10 separate audio channels, each channel pair with remote gain control, and a pair of 30-band EQT equalizers... well, I guess it isn't all that basic now that I think about it. But the point is, it is nothing but an audio system: no GPS, no third party apps or games, just a music player.


Tony: If Mark compiled you a special Hijack that didn't do the dock detection, would you be willing to install it and test it for him?


Sure. It only takes a few moments to do the kernal installation, and I can always revert back to the stock kernal.

Oh, and BTW, I should have mentioned this in my original post, I am running v.2.0 final player software and emplode.

tanstaafl.

Mmm.. When Hijack forcibly alters the "power setting" at boot, it pops up a 2-second message indicating such. But in a car environment, that message would be really easy to miss seeing.

So perhaps I'll just have it keep that info around for the Vitals screen, and that way when we see it do something funny, one can then look at Vitals and find out what Hijack had in mind..

I'm on the road right now (though I do have the complete build environment with me..), so it may be a day or two for this.

cheers

Well.. any luck with the special hijack version I provided for you?

Cheers

Well.. any luck with the special hijack version I provided for you?


Not at present... but not through any fault of yours.

I suppose it is a bad sign when I boot up my computer at home and Windows tells me that I may have hard drive prolems and runs scandisk with surface scan, and every time I do it it finds 40 or 50 more bad blocks than it did last time, all in a row.

Naahhh... it's probably just because I haven't set my ScanDisk parameters correctly. Yeah, that must be it.

So, until I can rebuild my computer I won't be doing a lot of testing. Hopefully early next week...

Sigh...

tanstaafl.

Last week I installed your modified kernal, and last night it finally mis-behaved, coming up in the car in AC mode. It did it consistently (pulled it out and re-inserted it three times) and here are the Vital Signs while it was misbehaving:

MK2:39gb +37C/+98F
Playlist: edb0, FID:
Powerstat=0xff01
Load avg: 0.57 0.29 0.11


This morning (after the player sat in the car all night, but removed from the sled) it came up normally, that is in DC mode. The Powerstat data this morning was: 0x7f00.

I assume these cryptic messages mean something to you? :-)

Yes. The first bit is the only important one in this case, indicating that the tuner_loopback (Home Dock) was detected. Which is odd, because the special Hijack I gave you performs the loopback TWICE, with differing data, just to make sure. So.. is your tuner connector touching metal?

Cheers

So.. is your tuner connector touching metal?

EMI / crosstalk? Maybe the tuner wire bundle is acting as an antenna somehow. I wonder just how freely the Rx pin floats.

Hijack v341 is now out. See if it helps (or not).

Cheers

So.. is your tuner connector touching metal?


Pretty unlikely, since I do not have a tuner installed in my car.

Hijack v341 is now out. See if it helps (or not).


I'll get it and install it before I go home tonight.

Thanks...

tanstaafl.

Pretty unlikely, since I do not have a tuner installed in my car.

No, that's exactly what he means: He means the dangly bit. The connector that would be connected to a tuner if you had one, but since you don't, has the opportunity to dangle and touch metal.

Another thing to check is if you've got this problem, and some of the tuner connector wires are touching each other.

He means the dangly bit

Ah! I understand now. No, there is no metal near the back of the sled. It butts up pretty tightly against a plastic defroster vent that we had to modify to fit the sled in.

...if you've got this problem...

I was aware of that problem before I installed the sled, and I tested it by pulling quite vigorously on the wires before it went into the car. I don't think there any loose wires... but it is impossible to tell for sure without removing the sled and that would definitely be a last resort.

tanstaafl.

Too weird.

Let me know if it goes away with Hijack v34[12].

Cheers

Let me know if it goes away with Hijack v34[12].

I installed Hijack v342, and the first time I put the player in the car it booted up in AC mode.

I don't know if this is significant, but when it boots in AC mode in the car, if I pull the player and reboot it always seems to come back up in AC mode. But if I leave it sitting overnight (possibly all I have to do is leave it until it goes out of standby mode?) it boots back up in DC mode.

Also, if it boots in AC mode, if I go into the HiJack menu to check and make sure that the AC/DC mode is indeed set to "Normal" (it definitely is!) and then press the left/right buttons to force reboot, it boots back up in DC mode.

As best I can tell, the serial connector and the tuner connector are not touching anything made of metal.

tanstaafl.

>As best I can tell, the serial connector and the tuner connector
>are not touching anything made of metal.

The results of the tuner loopback test STRONGLY suggest otherwise. As does the "after a cold (overnight) start it often works correctly" hypothesis.

Here's why it's going into AC mode: Hijack simply configures the Tuner serial port (on the tuner connector, not the regular serial port) and sends two bytes of data out on the TX line. It listens and receives two bytes from the RX line. It compares the two bytes, and if equal, it KNOWS that the tuner connector has been wired for loopback to signal "AC/Docked" operation.

Moisture from the air-conditioning, perhaps? Bare wires on the docking connector sometimes touching? The tuner connector brushing against something (it normally just dangles in space, so check it!) ?

I can easily "mask" the problem for you, but something may get permanently damaged if the short is never found/fixed.

Cheers

Here is the loopback detection code, from drivers/char/serial_sa1100.c (attached). The caller presets "loopback" to zero before calling into this code.

-ml

In parallel with all of this, I have added a "No-Loopback" setting to the Force Power Mode menu, which can be used to mask the hardware problem.

This will be included in Hijack v343, to be released shortly.

Cheers

Another slender possibility - chafing of the internal connector wires by the hard drive tray.

Moisture from the air-conditioning, perhaps?

This is Alaska, in late September. Air conditioning? We dont need no steenkin' air conditioning!

I'll go ahead and pull the sled out and take a very close look at all the wiring and wrap up and insulate any dangling conectors (i.e, tuner, serial) and see if the problem goes away.

tanstaafl.

Sure. Meanwhile, Hijack v343 is available, with the "No-Loopback" option under the "Force AC/DC Power Mode" menu.

Cheers

Meanwhile, Hijack v343 is available, with the "No-Loopback" option

But then I'd never find out if I do indeed have a hardware problem (connector touching metal, etc.) and what would be the fun of that? I'll pull the sled, insulate everything back there, and see if I can get the problem to happen again. If it does, then I'll put in the v343 amd make it stop.

Thanks, Mark...

tanstaafl.

see if I can get the problem to happen again

I haven't pulled the sled yet... but the problem did recur today, and I noticed something that might be significant.

The player started up in the car in AC mode, and through three restarts it always resumed in AC mode.

When I went to HiJack and checked that AC/DC was set to Normal (it was) and then had HiJack reboot the player it came back up in DC mode. This seems to be a recognizable pattern -- when it starts in DC mode, it stays that way until I force a reboot through HiJack, or else leave it in the car long enough to go off of Standby mode. Even pulling it from the sled and re-inserting it doesn't seem to make it restart in DC mode, but rebooting through HiJack does.

tanstaafl.