Rockbox Technical Forums
Support and General Use => Audio Playback, Database and Playlists => Topic started by: inot on August 24, 2007, 04:55:01 AM
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i've got old version of rockbox (version: r13302-070501). And i'v played mp3 without any problems, i've tryed to install new version (r14444), after this update i heard strange noise. I've tryed to format my ipod nano, and reistall (not upgrade) my rockbox, but artifacts didn't disappeared. i've install my old version of rockbox, and artifacts have gone.
artifacts = distortion
how can i solve this problem?
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I have the same problem on hot days. Cooling my iPod nano down helps with the problem, so it's obvious the problem is actually overheating. This probably only applies to specific batches of devices (or even individual devices!) which are used in warmer climates or seasons. People in colder areas aren't necessarily seeing the bug even if the possibility of it exists in their iPods.
This makes sense, because builds made before 26th July (15:07
"Clean up PP502x CPU clock setup code and use the full 80MHz when boosted.") seem to work fine, ie. it has been this clock speed raise from 75MHz to 80MHz that has made some devices unrealiable.
During the +25-30°C weeks here in finland it was practically impossible to use my iPod due to the glitches and skipping (and eventually the data aborts etc).
These threads are probably related to this:
http://forums.rockbox.org/index.php?topic=12336.0
http://forums.rockbox.org/index.php?topic=11817.0
Edit: forgot to mention this:
On hot days, when the device is overheating (it really feels hot!), even Windows sees garbled data on the device (when plugged in through USB). Filenames and directory names are corrupted, et cetera. Overheating -> I/O errors -> faulty reads from memories -> skipping MP3 playback (now that I mentioned it, it sounds 100x times worse than all those mp3's downloaded by modem back in the day) and corrupted MFT entries. Also, the corruption isn't non-volatile, so it isn't flash-based, but rather happens at the I/O processor.
Edit2: http://www.rockbox.org/tracker/task/7510?histring=7510 - here's the link to the tracker for what is probably this bug.
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This is most likely coincidence, we've just had someone take a hairdryer to their working Nano and not show symptoms despite it being quite hot to the touch.
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Still, I'm a bit curious - my nano works perfectly well on below-20°C days, but over 20°C starts to show symptoms. The degree of symptoms varies significantly with the ambient temperature.
We need a larger sample of devices to rule out this possibility.
Edit: There are a couple of cases in the ticket comments that could be related to heat problems, such as these:
http://www.rockbox.org/tracker/task/7510#comment17288
http://www.rockbox.org/tracker/task/7510#comment17032
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No, a single device rules this out as being a cause. If this were a cause it would work globally. More devices would simply show that cooler temperatures mitigate the problem, or that the heat increases its likelihood, but it's been shown that Nanos exist that do not show these symptoms under heat, so heat alone is not the cause.
As well, I live in Texas. It's bloody hot. Mine's never showed the problem. I took it to Puerto Rico. Where it's quite hot as well. No problem. Heat may make it more likely, or your personal one may have some form of damage drawn out by the heat that causes similar symptoms, but heat alone is not the cause of this problem.
And as to your quoting comment17288 as an example, it actually supports my point: Vorbis is generally less load on the iPods than MP3 right now, due to differing states of optimization. As well, FLAC uses vastly less, and seems to trigger it often for some people.
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So what you're saying is basically that we shouldn't investigate this particular cause at all because everything works on one device despite applied heat?
What if some 60% of Nanos display the heat problem while 40% work well? Should the development of Rockbox be stopped for those 60%, as they would be forced to use the last revision that used 75MHz clock?
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If 40% don't show the heat problem, then heat isn't the cause of the problem, it just draws out the symptoms, and there's still a very real chance we can actually identify what the problem is, rather than what makes the problem more visible.
We already have non-working iPods, and we *know* that 80mhz is a valid speed for the processor, so if hot environments are the problem, or if they're not, then we're not utilizing some other chip right. Rather than turning the processor down from 80mhz, we should be identifying what chip we're using wrong because whether or not hot environments are related, it's clear they don't *cause* the problem, just *highlight* it, and therefor investigation should be toward what actually causes it.
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I'm from Vietnam, and the tempature is usually above 30C here, and I haven't seen your symptoms during summer (sometimes the tempature raise to 35C). So I think the problem isn't because of the heat.
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We already have non-working iPods, and we *know* that 80mhz is a valid speed for the processor
Point taken.
we should be identifying what chip we're using wrong
This would probably be the i/o chip, since at least I've had problems during USB access. Someone with more knowledge about the data paths of the Nano could probably tell more.
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You're the only person who's experienced problems during USB access, and USB is not in any way controlled by Rockbox, so if the problem does relate to USB access, it's a hardware flaw and nothing we can fix.
We reboot into Apple software for all USB operations.
That information actually suggests that you're a unique case, as I don't believe anyone else has reported USB troubles.
Either way, as I've said somewhere, though I can't remember where, the current theory is that it's a timing issue accessing the flash. But again, this wouldn't affect USB since our software isn't running, and hasn't done any hardware init for that mode.
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Oh well, it only happened once, and before that I had used my iPod for some 2 hours despite the constant glitches... ::) I guess it could have been from the heat. Haven't had problems before that or after that.
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Okay, I did some research (and downgraded back to 13390). It's +11 outside and YES, skipping occurred during my cycling trip. ;D
I guess this rules out the possibility of the clock boost being the source of the problem. It makes it much worse, yes, but it does not cause it. Personally, I'm thinking the problem lies within the bootloader, since my problems started when upgrading a over-a-year-old build and bootloader to current.
Original iPod firmware runs fine and does not skip.
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You shouldn't be using an SVN current bootloader, you should be using the one included with ipodpatcher (which is many months old, and is unlikely to be the cause as we would've had months for people to report the problems before reports started showing up).
As well, we've already discovered something is questionable about your unit specifically and heat, since you had difficulties with USB mode.
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you should be using the one included with ipodpatcher
... which is what I'm using. I'm not crazy enough to compile anything myself. ::)
As well, we've already discovered something is questionable about your unit specifically and heat, since you had difficulties with USB mode.
It would be interesting to know what it would be. Aside from the heat, problems seem to be very random. The device is about 1,5 years old though, surely the flash chip couldn't be at the end of its lifetime yet?
Edit: Someone has had USB troubles: http://forums.rockbox.org/index.php?topic=12354.0
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Hi, I too have the same problem with my nano 1st gen... I used rockbox for 6 months without problems, updated builds every so often again with no problems. I think the last time I upgraded without a problem was around June... I even compiled my own build for the fun of it without problems again.
Now ever since the begginign of august (around) I attempted to upgrade my build and I 've had nothing but problems. I hear noise in the playback. Like you guys say Artifacts or whatever.. seems the song is playing a tad fast and eventually it starts buzzing out with weird sounds. It seems i can listen to my ipod for about 2 songs untill the problem starts. heat or not heat it does it everytime i play for more than 10 minutes. This really sucks... I can;t even listen to music anymore. I have now downgraded build to 20070726 hopefully this will work I will let you know sometime soon after using it for a while. If its any help i've had my nano for I think 2 years.. I got it shortly when it came out.
I sure hope you guys fix this cuz staying a few builds back would suck.
Thanks in adv,
SuPA