Messages in this thread | | | Date | Tue, 9 Sep 2003 16:51:06 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [linux-usb-devel] [2.6-test] Bug in usb-storage or scsi? |
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On Tue, 9 Sep 2003, Georgi Chorbadzhiyski wrote:
> Hello, > I was able to access my Music Pen mp3 player using usb-storage driver > in 2.4 without any problems. After updating to 2.6 this was not possible > anymore. It seems that usb-storage driver in 2.6 detect the device but > I was unable to access /dev/sda1. "mount -t vfat /dev/sda1 /mnt" returns > this error: "mount: /dev/sda1 is not a valid block device" > > Under 2.4.21-ck3, sda1 is corectly registered. > > Please see the attached files containing dmesg snippets from 2.4 and 2.6 > kerneles as well as 2.6 config. If you need more information I'll be glad > to provide it. > > The 2.4 kernel that I tested was 2.4.21-ck3 > The 2.6 kernel that I tested was 2.6.0-test5-mm1, 2.6.0-test4 and 2.6.0-test1
More problems with that stupid MODE-SENSE cache page! There are so many USB storage devices that have problems with that -- I wonder if it's worth the effort to try to continue supporting it?
Georgi, the problem is with your mp3 player, not usb-storage or SCSI. It's crashing when given a perfectly legal SCSI command. Linux 2.4 doesn't issue the command; that's why it works okay.
If you want a temporary fix for 2.6.0, you can do this: Edit the routine sd_read_cache_type in the file drivers/scsi/sd.c (near line 1100). Get rid of (or #ifdef out) most of the function; just leave the last few lines where it does:
printk(KERN_ERR "%s: assuming drive cache: write through\n", diskname); sdkp->WCE = 0; sdkp->RCD = 0;
You might want to change the KERN_ERR to KERN_NOTICE.
However, you might also want to think twice before doing this if you have any other SCSI disks, because making this change will affect all of them.
Alan Stern
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