Hi all,

Connecting mobile phones to the usb ports onl my acer c720 running debian sid/xfce4 gives strange results.

With android 4.0.4 phone, the device shows momentarily in (for example) thunar, then disappears, reappears. It continues to toggle on and off once a second. On the phone, the USB connected symbol in notifactions area similarly toggles on and off once a second.

With iphone 4s, the device shows in thunar for about a second then disppears.

There is another, general, issue with the USB ports that may be related. When a pendrive is inserted, the user account has read only access and cannot write files to the pendrive. This is corrected by running a little script:

sudo umount /dev/sdb1
mount /dev/sdb1

so that the machine knows it has been mounted as user.

With the Android device this is not a huge problem as files can still be transferred by bluetooth, but Apple does not allow its users to use bluetooth to transfer (eg) photos from an iphone to a personal computer.

How to begin to understand and correct this?

Thanks in advance...

Andrew.

Hi aal, list the contents of your /etc/fstab file for us please.
Let's see if there is anything there that can be improved.

Hi qlue,

Please find fstab following:

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
# / was on /dev/sda1 during installation
UUID=3yyyyd41-8a7a-4ade-afbb-8ec85xxxxxf4 / ext4 errors=remount-ro 0 1
# swap was on /dev/sda5 during installation
UUID=88yyyyy1be-b58f-4ad6-995f-d845xxxxx919 none swap sw 0 0
/dev/sdb1 /media/usb0 auto rw,user,noauto 0 0



thanks....

aal.

I would suggest that you comment out the last line by adding a '#' in front of it. That may fix the usb issues or it may have no effect.
I would also comment out the line for the swap partition, or even remove it completely. You really don't want your machine to start swapping on an SSD as it will probably hang.

There are a few possible reasons that might cause usb issues that are harder to determine. If the hardware is exotic enough, the Linux kernel drivers may not be fully compatible with that hardware. Or, there may be issues in SID that are causing hassles.

Is there a special reason why you are using SID? Have you tried Debian Stable on this machine?

Hi,

a few points. Have tried debian stable (in April). Kernel rev was too old for the video, patches for trackpad were not available, suspend resume was unfixable etc etc. This may have changed in the intervening months but I don't recall what kernel wheezy is running. Have tried debian testing/jessie more recently July/august, which was okay for most functionality but not all. Only sid works. Actually sid worked perfectly in April, but when I had to rebuild the machine in August, there had been an upgrade which rendered bluetooth inoperable. I had to downgrade one of the wayland packages. But these USB issues were always present, even when I was running sid as it was in april 2014.

Before this machine, my old laptop was running suse 12. Both kinds of mobile phone - iphone and android - connected fine on usb port, and could transfer files, so I don't think it is about kernel drivers not being up to the hardware.

I have also previously, in April, played with that last line in fstab, but I never thought of commenting it out. Will try.

As for swap on SSD, I remain unaware of the issue that causes SSD machines to hang. Please explain? I have been using swap since I got the machine and never had any problem (that I know of!). If I do comment the swap line out, what happens to the 770MB of SSD that I have setup as the swap partition??? Is it just wasted? In retrospect, seeing how I actually use the machine in practice, I really can do without swap, and not using it may also help with another little bug (going into hibernate mode). But if I do that, I'd like to recover the space into the main partition so that it can be used. After all, the (16GB) SSD is small enough as it is, and should not be wasted.

Thanks...

Andrew.

Hi Qlue,

Commenting out the /dev/sdb1 line in fstab helps. My android phone is now connecting as expected. Thank you.

I feel the iphone should now be working too, but I am not familiar with iphone. When connected on usb port, it does not yet show in thunar/file manager. May be an apple permissions settting?

Will look into this a bit more and post again.

Please do advise about Swap and SSDs.

Andrew.

SSDs have a much slower write speed than read speed. (about 25 times longer to write +-)
When you run out of ram, Linux writes some ram to swap to free up space. Because of the slow write speed, this takes too long and more ram gets used in the mean time causing more to need to be written.

In theory, once everything has been written to swap, the machine will return to normal, but in practice it never does. I found this out the hard way on my old netbook.
You won't see anything wrong until the machine tries to use swap and then it's too late, you have to pull the battery to get it to stop.
If it's at all possible, put a proper hard drive in instead.

BTW, this is a problem for flash storage in general. SD cards and USB flash drives are just as bad or worse with swap use.

As already advised, the android phone is now working fine but the iphone does not work. In thunar, it shows the same as before: appears for one second then disappears.

My understanding is that, when plugged in on a usb port, the iphone should present a dialogue to the user asking if they want to accept the connection. The iphone does vibrate when plugged in, but no dialogue appears.

Using lsusb on the pc gives:

Bus 001 Device 031: ID 05ac:12a0 Apple, Inc. iPhone 4S

So I think linux is aware of it and should not be the problem??

It looks like the iphone is automatically declining the connection without asking the user. Unfortunately, this particular iphone is setup in spanish and I still can't find out if this is right or how to turn it off.

andrew.

I found this bug which may be related.
Apple products are notorious for not talking to non-Apple devices and it's always hard to figure out how much of this by design.

I suggest you open a new thread specific to the iPhone issue as I believe that the more generic issue here is now solved. (and my knowledge of iPhone is non-existent)

Yes agreed.

Thanks again for this interesting bug report. Upgrading the linux kernel has introduced the problem on some machines. Apple modified ios to change its handling of linux (may be a factor for me as this iphone was working on my old suse 12 machine, whilst the original operating system in this phone predates the bug report by many months. Not sure when/if IOS was last upgraded).

Also there are various solutions (involving fuse and/or libimobiledevice) which may have worked for some users on some linux distros.

Will try all this out, then start new thread as required.


Andrew.

I've never seen, nor heard of, such a problem with using swap on an SSD. I've been doing it for years, and never had a problem.

Yes. I feel that such a problem would depend also on the memory architecture of the machine. perhaps that particular netbook fell over for want of sufficient cache?