DVD's sometimes mount, sometimes don't.

[besonian]

This sort of problem, I know, has had quite an airing at one time or another, but in all that I can find no answer to what's happening in my new KDE4 install. I had used Gnome since the launch of KDE4 because I felt there were too many problems with the latter for me to be able to rely on it. I've since been trying out the developing KDE4 on two other machines and a couple of days ago I came to a point where I was happy enough with it to put it on my main machine again. Specs of that -

Mobo - MSI K9VGM-V
CPU - Sempron 3800+ 64 dual core
RAM - 2gb Crucial DDR2
Video - Nvidia 6600 128mb

Everything was going fine until I started trying to play DVD's. Sometimes they will mount, sometimes they won't - even within the same session with no reboot or logout/login involved. I've tried to find some consistency in this. I've tried adding the suggested (in the PCC) entries to fstab. I've tried changing those to those suggested in another thread by O-P. I've tried that with and without configuring KDE to mount removable media at login and when they are attached. And I've tried commenting out the entries in fstab along with both configuring KDE to  mount them automatically and not configuring it to do that.

Result is the same. Most times, just after I boot, the DVD will be recognized and the little box come up offering a number of options. Click on play with VLC or Kaffeine for example and it does just that. Try the same thing say an hour later, and although I may hear the disc spin up, nothing will appear on the screen. Clicking on the Device Notifier tells me that there are no devices available. If I launch VLC for example and ask it to play the DVD (yes, it knows where to look) I will be told the device is not readable.

A few minutes back I installed the 2.6.33.7-pclos6-a64 kernel in the hope that had something to do with it. At the moment the machine is behaving itself - but that's just after a reboot when it usually behaves itself anyway. Can  anyone throw some light on this? Do the words HAL and udev have any relevance here? Next week I have to update the computer of a couple in their late middle-age who I converted to Linux a couple of years ago. Since then they have been 100% trouble-free. They know nothing (nor are they interested) about computers or Linux and I'm just a little nervous of putting KDE 4 on their machine if this is anything to do with the OS. Or is it a hardware problem and related only to this main machine? I have to say, the other two machines I've been testing KDE4 on haven't played up this way - so far.

[Bald Brick]

besonian,

A video DVD does not have to be mounted. It may actually be preferable that it isn't when you watch it, and your video players will play it without mounting it.

That said, I've sometimes stumbled over the same problem as you: that a player won't recognize a DVD video disk. I've never considered this a very serious problem though: removing the disk and reinserting it will usually make it accessible again.

[besonian]

Bald Brick - thank you. OK, my terminology's a bit at fault here, sorry about that. But I've tried putting the disc straight back in again - and nothing works. Nothing I can think of if the machine takes it into its head not to play ball. And on that subject - in my previous post I said I'd installed a later kernel and that it was recognizing DVD's as it should. Now - an hour or so later, with no logout/login and no reboot - and with the very same DVD - insert it in the player  - nothing. And trying to play it from VLC gives me the message - Playback failure. DVD read could not read the disc - /dev/sr0. Is there a hardware problem? What it might be I've no idea because when the player plays it works perfectly. I'm lost with this one. I'm even starting to wonder if I should either put off updating this couples' computer until I know more about this fault - or should I go back for the time being to Gnome? Decisions,  decisions. Computers! 

[Was_Just19]

If you have entries for optical media in your fstab file I suggest commenting them out (#) or deleting them.

Do you have more than one optical drive in the system?

If so you may wish to create a separate entry in the Device Notifier for each ...  particularly if using VLC, which defaults to just one drive.

I do not 'Automatically Mount Removable Media" either ......  you might turn this off if it is set.

[Bald Brick]

If it happens consistently I'd first of all try cleaning the laser lens in the DVD player. If you can reach it, clean it with a cotton swab and a few drops of alcohol. It should be isopropyl alcohol but in a pinch even strong vodka will do. (This will give me an avalanche of protests, but I've actually used vodka with good results: the alcohol should just be pure enough.)

I you can't reach it, get a lens cleaning disk: it won't be as effective but it will usually do its job (even if there have been reports that some lens cleaning disks may actually scratch the lens).

If the disk doesn't help you may have to remove the casing of the DVD player so as to make the lens reachable with the cotton swab and alcohol.

Edit. To add to Just19's post. I take it that /dev/sr0 really is the drive you are trying to use?

[besonian]

OK guys,  thank you. Bald Brick - I'll try cleaning the lens. And yes, /dev/sr0 is indeed the drive in question and the one I've set VLC to look in.

Just19 - the one variation I don't think I've tried is commenting out any fstab entries (already done) along with turning off 'Automatically Mount Removable Media'. That's next.

I'll try these and report back tomorrow -  it's 2145  now in the UK.

[Xero]

How old is the dvd drive? I had this issue with one optical drive, read some discs, not others, or read some with great difficulty. Switched to another drive laying around and all good. Hardware issue.

[besonian]

Thank you guys for all your input. I've been away for a few days, hence my absence from this thread.

Not sure where to start - it turned out to be a real headache. The first clear thing is I decided I daren't put KDE4 on that couples' computer. I decided against Gnome because although I like it, it too is reputed to be coming up for a major refit in the new year and I didn't want to hit the same problem - sorry Gnome devs if I'm maligning you here  - that of two rather conventional people in late middle-age having to cope with (they wouldn't) the sort of problems KDE4 hit in its earlier days. So I decided on LXDE or XFCE for them.

The headache I had with my DVD problem got me to a point of despair. I could figure out no consistency in what was happening. E.g - I tried re-installing Gnome (this is on my main machine) The medium was checked, checksum done etc. On the first attempt the machine suddenly dropped me to a shell halfway through the install. On the second attempt it did the same part-way through the updating after the install. The third time all went well until I rebooted after the install and it took me to the splash screen - then no further. Total freeze even with Skinny Elephants. Rebooting took me to the same point every time and no further. And by this time, in between all this, I'd run memtest for two hours, I'd run full disk reads on both drives and I'd changed the DVD writer for a new one. The only thing I hadn't checked because I've no diagnostic tool I'm aware of to check it. But I thought that unlikely anyway. The only thing left was the motherboard. I ordered a new one from Ebuyer which turned up the following day. I installed LXDE (I wasn't risking KDE4 again) and was up and running very soon after, no problem.

So what it was about I'm still not sure. Was it the mobo? I'm still not sure - and for a good reason which I'll cover in another thread with a link back to this one. It may be that the two problems are connected.

Anyway, thank you guys again.