MX Linux Forum

BitJam wrote:

Eadwine Rose wrote:Then explain to me why this was never an issue in earlier Mepis versions, and ONLY started creeping up in MX14? THAT is what I don't get.

Have you tested it to see if the problem now occurs with older kernels? I don't think it will but if it does then that means it is a hardware problem the developed around the time you started using MX-14.

BitJam wrote:

qtech wrote:Something believes the Plextor is a SCSI Hard Disk.

That "something" is the kernel, which was determined from ER's system log a while ago. Here is an excerpt from the most recent system log:

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Mar  5 13:15:42 eadwinemx14beta2 kernel: [    2.973162] ata1.01: ATAPI: SONY DVD-ROM DDU1612, DYS1, max UDMA/33
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    2.989093] ata1.00: configured for UDMA/66
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    2.989748] ata1.01: configured for UDMA/33
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    2.991649] scsi scan: INQUIRY result too short (5), using 36
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    2.991656] scsi 0:0:0:0: Direct-Access                                    PQ: 0 ANSI: 5
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    2.992101] scsi 0:0:1:0: CD-ROM            SONY     DVD-ROM DDU1612  DYS1 PQ: 0 ANSI: 5
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.016708] ata4: SATA link down (SStatus 0 SControl 300)
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.016773] ata5: SATA link down (SStatus 0 SControl 300)
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.016808] ata6: SATA link down (SStatus 0 SControl 300)
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.048697] usb 6-6: new high-speed USB device number 4 using ehci-pci
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.188644] ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.189769] ata3.00: ATA-8: WDC WD5000AAKS-00WWPA0, 01.03B01, max UDMA/133
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.189773] ata3.00: 976773168 sectors, multi 16: LBA48 NCQ (depth 31/32), AA
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.190958] ata3.00: configured for UDMA/133
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.191152] scsi 2:0:0:0: Direct-Access     ATA      WDC WD5000AAKS-0 01.0 PQ: 0 ANSI: 5
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.196115] sr0: scsi3-mmc drive: 40x/40x cd/rw xa/form2 cdda tray
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.196123] cdrom: Uniform CD-ROM driver Revision: 3.20
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.196309] sr 0:0:1:0: Attached scsi CD-ROM sr0
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.198163] sd 2:0:0:0: [sdb] 976773168 512-byte logical blocks: (500 GB/465 GiB)
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.198245] sd 0:0:0:0: Attached scsi generic sg0 type 0
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.198279] sd 2:0:0:0: [sdb] Write Protect is off
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.198282] sd 2:0:0:0: [sdb] Mode Sense: 00 3a 00 00
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.198338] sd 2:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.198342] sr 0:0:1:0: Attached scsi generic sg1 type 5
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.198501] sd 2:0:0:0: Attached scsi generic sg2 type 0
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.199311] sd 0:0:0:0: [sda] READ CAPACITY(16) failed
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.199315] sd 0:0:0:0: [sda]  
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.199317] Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.199319] sd 0:0:0:0: [sda] Sense not available.
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.204706] sd 0:0:0:0: [sda] Write Protect is off
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.204712] sd 0:0:0:0: [sda] Mode Sense: 00 da 70 00
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.206883] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.217923] sd 0:0:0:0: [sda] READ CAPACITY(16) failed
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.217928] sd 0:0:0:0: [sda]  
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.217930] Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.217931] sd 0:0:0:0: [sda] Sense not available.
Mar  5 13:15:42 eadwinemx14beta2 kernel: [    3.224647] sd 0:0:0:0: [sda] Attached SCSI disk

It is the kernel that assigns the name sda to the dvd drive. The first time sda appears in the log is in a message that READ CAPACITY failed. I asked for the blkid output for extra confirmation the name sda is coming from the kernel (and not from udev) but when the error condition occurs, the sda device does not show up in the blkid output or in /proc/partitions or /proc/sys/dev/cdrom/info. It is not just a naming problem, the kernel is confused and cannot access the device.

The first error is:

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scan: INQUIRY result too short (5), using 36

Google(INQUIRY result too short) yielded a lot of hits. One [url=http://comments.gmane.org/gmane.linux.scsi/74353]succinct explanation was:

Well, it means what it says: the device wrongly returned only 5 bytes
for the INQUIRY command. Why it did this is a hardware issue.

qtech wrote:Technically, it is correct that the Plextor theoretically could be legitimately recognized a SCSI disk drive

This is simply not true. It is either a problem with the hardware/harware-configuration or it is a bug in the kernel. If the hardware is working correctly then dvd drives should always be recognized as dvd drives, otherwise it is a bug in the kernel.

You have IDE, AHCI and USB all trying to mount drives at roughly the same time.

As I said before, I don't think physically different buses are directly affecting the IDE bus. That would be rather magical. Although it is possible they are affecting each other indirectly via the power supply. It takes a lot of power to spin up a hard drive (or even an optical drive). If they are all spinning up together then maybe this causes a small dip in the power that affects the Plextor drive. As I've said before, it is now legitimate for the device names to change each boot due to race conditions between the various devices becoming available. But it is not legitimate to classify a dvd drive as a hard drive.

Part of the issue here is the timing in which these drives detect and mount (and thus why it is an intermittent problem, the timings are not always the same.

I'm glad we agree.

The solution is going to be to manipulate that timing.

This may fix the problem but if so, it is a work-around, not a solution. IMO, once we have ruled out a hardware/hardware-config problem then the next step is to report a possible kernel bug.

I like your idea of swapping the jumper config on the Sony and Plextor drives. It will be interesting to see if the problem really does affect the Sony as well. This would help rule out that something in the Plextor drive is contributing to the problem. Another thing to try is to disconnect the Sony and see if the problem persists. I also like your idea of swapping out the ribbon cable. Just unplugging and replugging the connectors might help. Physical connectors have a relatively high failure rate, although it is curious that the problem always manifests the same way. Faulty connectors should create random errors whenever you access the drives.