Problem solved for Asus A6Rp laptop --FIRMWARE UPGRADE REQUIRED --
Following other successful stories (see above) regarding firmware upgrades on a number of laptops I decided to attempt a firmware upgrade myself. The Asus A6Rp has a TSSTcorpCD/DVD TS-L632D optical drive which came with firmware version AS05. Asus appears to provide no drive firmware upgrade - so cross-flashing is required. But first, some background.
TSST stands for "Toshiba Samsung Storage Technology". Samsung provides these drives in their own laptops but they also provide them to other laptop companies such as Asus, Acer, HP and others. If you have a Samsung laptop your firmware version will likely begin with SC (however other possibilities exist). I have an ASUS so the firmware has been labeled ASxx. More on this if you goto http://www.samsungodd.com and then FIRMWARE->Check F/W VERSION. Samsung appears to provide a customised firmware product to other laptop companies. However, Samsung only supports their drives in their laptops. Other laptop companies must pass on firmware upgrades independently, which in the case of ASUS doesn't appear to be happening. Some other laptop companies may do this- you'll have to check.
A quick web search shows that these drives are causing trouble for numerous OS platforms including MSwindows (although the problem manifests itself a little differently on MSWindows). I'll assert at this point that I think this bug is not an Ubuntu bug nor is it a Linux kernel bug: it is a manufacturer firmware bug. However, having said that, I am very grateful that this did exist as a bug in Ubuntu's Launchpad because world-wide, Launchpad has been the best source of information about this problem with some excellent discussion and ideas.
For me the only solution available was to cross-flash with SCxx firmware to replace my buggy AS05 firmware and hope that the differences between the custom AS05 and SCxx are negligible. It seems that in the case of the A6Rp the differences are indeed negligible or perhaps non-existent.
You can check your drive and firmware version in Ubuntu by going: System>Preferences>Hardware Information ; Now look for your drive. Under the "advanced" tab you will find > 'info.product' & also 'storage.product' which will say something like "TSSTcorpCD/DVD TS-L632D" ; and, 'storage.firmware_version' which may say "AS05". Alternatively, you can download "WININQUIRY.EXE" from http://www.samsungodd.com and then FIRMWARE>Check F/W VERSION and run this in MSWindows or run it in Ubuntu using wine (It works perfectly with wine in Ubuntu feisty).
Note that some laptops that have Samsung drives which are not model TS-L632D are reported to have been successfully flashed with the SCxx firmware for the TS-L632D drive (see Andreas on 2007-08-04 above in this bug commentary).
Below I outline my solution and I also provide reference to a solution if you don't have an MSwindows partition.
Solution for A6Rp - if you have a bootable MSwindows partition:
You will need the firmware upgrade from Samsung. There are two firmware upgrade versions available SC03 (dated 2007-02-08) & SC04 (dated 2007-06-12). I used SC03, it solved the problems so I stopped there. Others have used SC04 without problem, but I can't vouch for SC04 on Asus A6Rp. Get these firmwares from Samsung at the following addresses:
Or, simply do a search in google for "TS-L632D_SC03.EXE" or "TS-L632D_SC04.EXE" and you will find them. The first thing you will notice is that these sites are in Korean language. I can find no English equivalent site. You can have google do a translation for you but the provided info isn't substantial. To download the required files you will need the untranslated site. The required files are written in orange text near the bottom of the page.
Once you have the required firmware, rename the file from *.exe to *.zip. Then the "Archive Manager" in Ubuntu can extract the required components (Note: this is a useful tip for anyone who wants to look inside an MSwindows self-extractable zip file). Now you will have two files "200702081154530571_TS-L632D_SC03.BIN" & "sfdnwin.exe". The *.BIN is the firmware and sfdnwin.exe is the Samsung optical drive firmware flash program. In Ubuntu copy them to your MSWindows partition. "sfdnwin.exe" doesn't run under wine as far as I can tell. You need to run it under MSwindows from a terminal window with the following command line "sfdnwin.exe -nocheck". "nocheck" lets you do a cross-flash. Just load the *.BIN file then do the flash. It's quick - about 20-30secs. Restart PC and boot up in Ubuntu and optical drive problem is solved.
Note that this firmware upgrade solves more than the problem discussed in this bug discussion. Other problems which I had assumed were Ubuntu or VLC bugs were also solved. These are as follows:
1/ Under firmware AS05 when viewing a DVD movie, if pause was used, VLC would produce jumpy output (ie. stop-start) after movie was restarted. Only solution was to restart PC. Restart of VLC didn't fix problem. After firmware upgrade to SC03 problem has gone.
2/ Under firmware AS05 when viewing a movie with VLC and using slider bar at bottom to navigate around the movie, VLC would often lockup. After upgrade to SC03 VLC works fine with slider bar navigation.
Solution for persons without MSwindows bootable partition:
I haven't tried this but it is reported to work for a type of System76 laptop.
See entry by Thomas Aaron (on 2007-08-13) in Bug #117441 .
Note that this is the same bug as reported here but this bug number is specific to System76 laptops. Thomas has come up with a neat solution for the Darter using two USB memory sticks. Perhaps the same (or similar) solution will work on any PC. If not, perhaps some smart Ubuntu/Linux person could come up with a similar generic solution?
Note that this solution uses the DOS version of Samsung's optical drive firmware flash program called "sfdndos.exe". Bug #117441 provides the required files as attachments.
Some important notes:
There is reference around the web to an AS99 firmware. I have only read bad reports about this. The version I saw was dated 2006 & the "sfdnwin.exe" was dated 2004. Some MSWindows users have reported that it erased their HD partitions others report no improvement to drive operation. I have found no official ASUS reference to this firmware version for my laptop and it appears to be only available from third party sites. My recommendation is STAY AWAY from this firmware unless you have some info that I don't. Goto SAMSUNG or your laptop company for your firmware & firmware flash program.
1/This cross-flash upgrade to SC03 works for the TS-L632D on the Asus A6Rp and COMPLETELY SOLVES this bug plus other problems. It probably would work for any TS-L632D. The SC03 and/or SC04 firmware for the TS-L632D also appears to work for some other Samsung drive models.
2/If you don't have a bootable MSwindows partition see Bug #117441 for a solution.
3/This bug is clearly not an Ubuntu bug nor a Linux kernel bug. It is a bug in the optical drive firmware from Samsung.
4/ Asus & Samsung would probably not recommend cross-flashing. However, as far as I can tell, there is no other choice if you want your optical drive to function correctly.