cs5520: disable VDMA

Disable Virtual DMA support for now (it causes system hangs).

Thanks to TAKADA Yoshihito for the help with debugging the problem.
Reported-by: TAKADA Yoshihito <takada@mbf.nifty.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/pci/cs5520.c

@@ -119,6 +119,7 @@ static const struct ide_dma_ops cs5520_dma_ops = {
 	.dma_timeout		= ide_dma_timeout,
 };
 
+/* FIXME: VDMA is disabled because it caused system hangs */
 #define DECLARE_CS_DEV(name_str)				\
 	{							\
 		.name		= name_str,			\
@@ -126,7 +127,6 @@ static const struct ide_dma_ops cs5520_dma_ops = {
 		.dma_ops	= &cs5520_dma_ops,		\
 		.host_flags	= IDE_HFLAG_ISA_PORTS |		\
 				  IDE_HFLAG_CS5520 |		\
-				  IDE_HFLAG_VDMA |		\
 				  IDE_HFLAG_NO_ATAPI_DMA |	\
 				  IDE_HFLAG_ABUSE_SET_DMA_MODE, \
 		.pio_mask	= ATA_PIO4,			\

include/linux/ide.h

@@ -1057,8 +1057,8 @@ enum {
 	IDE_HFLAG_NO_SET_MODE		= (1 << 9),
 	/* trust BIOS for programming chipset/device for DMA */
 	IDE_HFLAG_TRUST_BIOS_FOR_DMA	= (1 << 10),
-	/* host uses VDMA (tied with IDE_HFLAG_CS5520 for now) */
-	IDE_HFLAG_VDMA			= (1 << 11),
+	/* host is CS5510/CS5520 */
+	IDE_HFLAG_CS5520		= (1 << 11),
 	/* ATAPI DMA is unsupported */
 	IDE_HFLAG_NO_ATAPI_DMA		= (1 << 12),
 	/* set if host is a "non-bootable" controller */
@@ -1069,8 +1069,6 @@ enum {
 	IDE_HFLAG_NO_AUTODMA		= (1 << 15),
 	/* host uses MMIO */
 	IDE_HFLAG_MMIO			= (1 << 16),
-	/* host is CS5510/CS5520 */
-	IDE_HFLAG_CS5520		= IDE_HFLAG_VDMA,
 	/* no LBA48 */
 	IDE_HFLAG_NO_LBA48		= (1 << 17),
 	/* no LBA48 DMA */
@@ -1100,6 +1098,8 @@ enum {
 	IDE_HFLAG_NO_IO_32BIT		= (1 << 30),
 	/* never unmask IRQs */
 	IDE_HFLAG_NO_UNMASK_IRQS	= (1 << 31),
+	/* host uses VDMA (disabled for now) */
+	IDE_HFLAG_VDMA			= 0,
 };
 
 #ifdef CONFIG_BLK_DEV_OFFBOARD