I'm having the same issue with trying to play DVDs. The drive worked perfectly about a week or two ago. (I don't use my DVD drive very often, so I am uncertain whether this problem occurred before or after updating to 8.10 RC.)

Relevant dmesg:

[38779.018260] end_request: I/O error, dev sr0, sector 15525888
[38779.018267] Buffer I/O error on device sr0, logical block 3881472
[38779.019766] end_request: I/O error, dev sr0, sector 15525892
[38779.019771] Buffer I/O error on device sr0, logical block 3881473
[38779.021129] end_request: I/O error, dev sr0, sector 15525888
[38779.021132] Buffer I/O error on device sr0, logical block 3881472
[38779.022523] end_request: I/O error, dev sr0, sector 15525892
[38779.022528] Buffer I/O error on device sr0, logical block 3881473
[38779.024093] end_request: I/O error, dev sr0, sector 15526096
[38779.024098] Buffer I/O error on device sr0, logical block 3881524
[38779.025495] end_request: I/O error, dev sr0, sector 15526100
[38779.025501] Buffer I/O error on device sr0, logical block 3881525
[38779.026971] end_request: I/O error, dev sr0, sector 15526096
[38779.026975] Buffer I/O error on device sr0, logical block 3881524
[38779.028535] end_request: I/O error, dev sr0, sector 15526100
[38779.028540] Buffer I/O error on device sr0, logical block 3881525
[38779.029939] end_request: I/O error, dev sr0, sector 15526112
[38779.029943] Buffer I/O error on device sr0, logical block 3881528
[38779.031341] end_request: I/O error, dev sr0, sector 15526112
[38779.031347] Buffer I/O error on device sr0, logical block 3881528
[38779.033018] end_request: I/O error, dev sr0, sector 15526112
[38779.034738] end_request: I/O error, dev sr0, sector 15526112
[38779.036216] end_request: I/O error, dev sr0, sector 15526112
[38779.037612] end_request: I/O error, dev sr0, sector 15526112
[38779.039017] end_request: I/O error, dev sr0, sector 15526112
[38779.040996] end_request: I/O error, dev sr0, sector 15526048
[38779.043579] end_request: I/O error, dev sr0, sector 15526052
[38779.045640] end_request: I/O error, dev sr0, sector 15526104
[38779.047043] end_request: I/O error, dev sr0, sector 15526108
[38779.048436] end_request: I/O error, dev sr0, sector 15526112
[38779.049822] end_request: I/O error, dev sr0, sector 15526112
[38779.409048] UDF-fs: Partition marked readonly; forcing readonly mount
[38779.498585] UDF-fs INFO UDF: Mounting volume 'KILLBILL_VOL1', timestamp 2004/03/01 20:51 (1ed4)
[38803.019171] end_request: I/O error, dev sr0, sector 522556
[38803.019179] __ratelimit: 11 callbacks suppressed
[38803.019182] Buffer I/O error on device sr0, logical block 130639
[38803.019188] Buffer I/O error on device sr0, logical block 130640
[38803.019191] Buffer I/O error on device sr0, logical block 130641
[38803.019193] Buffer I/O error on device sr0, logical block 130642
[38803.019195] Buffer I/O error on device sr0, logical block 130643
[38803.019198] Buffer I/O error on device sr0, logical block 130644
[38803.019202] Buffer I/O error on device sr0, logical block 130645
[38803.019205] Buffer I/O error on device sr0, logical block 130646
[38803.019208] Buffer I/O error on device sr0, logical block 130647
[38803.019211] Buffer I/O error on device sr0, logical block 130648
[38833.896034] ata4.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
[38833.896044] ata4.00: cmd a0/00:00:00:00:00/00:00:00:00:00/a0 tag 0
[38833.896045]          cdb 1b 00 00 00 02 00 00 00  00 00 00 00 00 00 00 00
[38833.896046]          res 40/00:03:00:00:00/00:00:00:00:00/a0 Emask 0x4 (timeout)
[38833.896049] ata4.00: status: { DRDY }
[38836.525025] ata4: soft resetting link
[38836.737299] ata4.00: configured for UDMA/33
[38836.737323] ata4: EH complete

I've tried several DVDs and nothing works. Sometimes, the kernel panics as well; I assume it's because of this because these errors are always the most recent in logs after rebooting from the panic.