Hi Folks, I use ATA pass through via sg ioctl interface for data read/write. Two kernels were tested: Linux 2.6.15.4 with Jeff Garzik's libata patch (pata support) Linux 2.6.18-rc2 with Jeff Garzik's git libata patch (new EH, hotplug, pata support) Hardware: ARM IOP80321 with PCI-X Host adapters: sata Sil3124 and pata Sil680 Test algorithm: random write-read-compare (same range) I've tried sg mmap, direct and indirect IO on both 2.6.18-rc2 and 2.6.15.4 release, none of the combinations survived data compare overnight test. I also tried to change cache policy to write through on 2.6.15.4, no luck either. Several different symptoms were observed among the failures: 1. A few bytes in a data pattern were not written correctly to the disc (low data miscompare rate) 2. Pretty much none of the data were written correctly to the disc (high data miscompare rate) 3. Data were written to the disc correctly but miscompares when read it back. What's weird is that when the read buffer was printed out right after data miscompare , it contains the correct data! Sg write failures (symptom #1 and #2) are more typical than read failure (symptom #3). This problem has been observed on many different test machines with both pata and sata drives. I don't know of a good way to trace and isolate the problem yet. Since data miscompare issue can be caused by issues from different subsystems, I cc'ed some subsystem maintainers here. Any information or suggestions are greatly appreciated. Thanks, Fajun - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
