From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Date: Mon, 29 Dec 2008 19:27:28 +0000 (+0100)
Subject: tx4939ide: Do not use zero count PRD entry
X-Git-Tag: v2.6.28.1~84
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=7ee9f07eca4a37c099dec3c700dfb3322320f5a3;p=karo-tx-linux.git

tx4939ide: Do not use zero count PRD entry

commit a0fce792b55b260589c3d77293a224e84395ec07 upstream.

This fixes data corruption on some heavy load.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: sshtylyov@ru.mvista.com
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/ide/tx4939ide.c b/drivers/ide/tx4939ide.c
index bb5a26bfc871..97cd9e0f66f6 100644
--- a/drivers/ide/tx4939ide.c
+++ b/drivers/ide/tx4939ide.c
@@ -259,6 +259,12 @@ static int tx4939ide_build_dmatable(ide_drive_t *drive, struct request *rq)
 			bcount = 0x10000 - (cur_addr & 0xffff);
 			if (bcount > cur_len)
 				bcount = cur_len;
+			/*
+			 * This workaround for zero count seems required.
+			 * (standard ide_build_dmatable do it too)
+			 */
+			if ((bcount & 0xffff) == 0x0000)
+				bcount = 0x8000;
 			*table++ = bcount & 0xffff;
 			*table++ = cur_addr;
 			cur_addr += bcount;