WAIT_DRQ and ATA flash

WAIT_DRQ and ATA flash

[Fabio Parodi]

Hi Guys,

We use a Samsung ATA flash as /dev/hda. Filesystem is ext3 but the same
occurs with minix. It worked fine up to kernel 2.4.10. But from kernel
2.4.11 (2.4.12) onward a troublesome problem crept in.

We fixed it by modifying the timeout value of WAIT_DRQ. 

IDE specs allow up to 20ms, standard Linux kernel allows up to
50ms, but Samsung ATA CF needs 100ms. 

What should we do? We have four options:

A - keep this patch for us. Stop bothering.
B - #define WAIT_DRQ (10*HZ/100) in standard kernel tree
C - put a parameter to be adjusted at boot time 
D - write some code that autoadjusts WAIT_DRQ depending on device type

We think that option B should not harm other users - after all, 
this timeout only occurs in case of errors. 

If you are interested in details, this is an excerpt from dmesg:

Linux version 2.4.16 (root@devel-linux) (gcc version 2.95.2 19991024
(release)) 
...
ide: Assuming 33MHz system bus speed for PIO modes; override with
idebus=xx
CS5530: IDE controller on PCI bus 00 dev 92
CS5530: chipset revision 0
CS5530: not 100% native mode: will probe irqs later
    ide0: BM-DMA at 0xfc00-0xfc07, BIOS settings: hda:pio, hdb:pio
    ide1: BM-DMA at 0xfc08-0xfc0f, BIOS settings: hdc:pio, hdd:pio
hda: SAMSUNG ATA CF, ATA DISK drive
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14 
hda: 123392 sectors (63 MB) w/1KiB Cache, CHS=964/4/32
Partition check:
 hda: hda1        
...


After one minute from the boot, the ide driver
prints these messages:

hda: status timeout: status=0xd0 { Busy }
hda: no DRQ after issuing WRITE
ide0: reset: master: error (0x00?)
hda: status error: status=0x59 { DriveReady SeekComplete DataRequest Error }
hda: status error: error=0x00 { }
hda: drive not ready for command
hda: status error: status=0x58 { DriveReady SeekComplete DataRequest }
hda: drive not ready for command
hda: status error: status=0x58 { DriveReady SeekComplete DataRequest }
hda: drive not ready for command
hda: status error: status=0x58 { DriveReady SeekComplete DataRequest }
hda: drive not ready for command
ide0: reset: master: error (0x00?)
end_request: I/O error, dev 03:01 (hda), sector 2
end_request: I/O error, dev 03:01 (hda), sector 16
end_request: I/O error, dev 03:01 (hda), sector 18
end_request: I/O error, dev 03:01 (hda), sector 20
end_request: I/O error, dev 03:01 (hda), sector 22
end_request: I/O error, dev 03:01 (hda), sector 24
end_request: I/O error, dev 03:01 (hda), sector 26
end_request: I/O error, dev 03:01 (hda), sector 28
end_request: I/O error, dev 03:01 (hda), sector 30       

The system becomes unstable.

Fabio Parodi