[PATCH ide] : Increase WAIT_DRQ to support slow CF cards

[Philippe De Muyter <phdm@macqel.be>]

Hi,

I just encountered a problem with write-access to a batch of CF cards
(KINGSTON TECHNOLOGY 4GB COMPACT FLASH CF/4GB
3.3V/5V 9904321 - 006.AOOLF 4449081 - 1219643 X001 ASSY IN TAIWAN (c) 2008)
connected to a PC-CARD / PCMCIA interface, with the following error messages :

	hda: status timeout: status=0xd0 { Busy }
	ide: failed opcode was: unknown
	hda: no DRQ after issuing MULTWRITE

After testing with different bigger values for the WAIT_DRQ timeout value,
the problem disappeared.  I had success with WAIT_DRQ = 500ms, then with
WAIT_DRQ = 300ms.  I then tested with WAIT_DRQ = 200ms, but the problem
reappeared.  So I kept the 300ms value.

Signed-off-by: Philippe De Muyter <phdm@macqel.be>

diff -r a145344bb228 include/linux/ide.h
--- a/include/linux/ide.h	Thu Oct 22 08:28:28 2009 +0900
+++ b/include/linux/ide.h	Mon Oct 26 16:51:23 2009 +0100
@@ -125,8 +125,8 @@
  * Timeouts for various operations:
  */
 enum {
-	/* spec allows up to 20ms */
-	WAIT_DRQ	= HZ / 10,	/* 100ms */
+	/* spec allows up to 20ms, but some CF cards need more than 200ms */
+	WAIT_DRQ	= 3 * HZ / 10,	/* 300ms */
 	/* some laptops are very slow */
 	WAIT_READY	= 5 * HZ,	/* 5s */
 	/* should be less than 3ms (?), if all ATAPI CD is closed at boot */