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Commit 8243e636 authored by Tejun Heo's avatar Tejun Heo Committed by Jeff Garzik
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pata_ali: disable ATAPI DMA 



ATAPI DMA just doesn't work reliably on pata_ali.  The IDE driver can
do it but for some mysterious reason, pata_ali can't.  This patch
disables it by default and makes the driver whine during
initialization.  "pata_ali.atapi_dma" parameter is added so that user
can bypass the workaround.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent e52dcc48

drivers/ata/pata_ali.c

+40 −0
Original line number Diff line number Diff line
@@ -36,6 +36,10 @@ 
#define DRV_NAME "pata_ali"

#define DRV_VERSION "0.7.5"



int ali_atapi_dma = 0;

module_param_named(atapi_dma, ali_atapi_dma, int, 0644);

MODULE_PARM_DESC(atapi_dma, "Enable ATAPI DMA (0=disable, 1=enable)");



/*

 *	Cable special cases

 */
@@ -269,6 +273,27 @@ static void ali_set_dmamode(struct ata_port *ap, struct ata_device *adev) 
	}

}



/**

 *	ali_warn_atapi_dma	-	Warn about ATAPI DMA disablement

 *	@adev: Device

 *

 *	Whine about ATAPI DMA disablement if @adev is an ATAPI device.

 *	Can be used as ->dev_config.

 */



static void ali_warn_atapi_dma(struct ata_device *adev)

{

	struct ata_eh_context *ehc = &adev->link->eh_context;

	int print_info = ehc->i.flags & ATA_EHI_PRINTINFO;



	if (print_info && adev->class == ATA_DEV_ATAPI && !ali_atapi_dma) {

		ata_dev_printk(adev, KERN_WARNING,

			       "WARNING: ATAPI DMA disabled for reliablity issues.  It can be enabled\n");

		ata_dev_printk(adev, KERN_WARNING,

			       "WARNING: via pata_ali.atapi_dma modparam or corresponding sysfs node.\n");

	}

}



/**

 *	ali_lock_sectors	-	Keep older devices to 255 sector mode

 *	@adev: Device
@@ -283,6 +308,7 @@ static void ali_set_dmamode(struct ata_port *ap, struct ata_device *adev) 
static void ali_lock_sectors(struct ata_device *adev)

{

	adev->max_sectors = 255;

	ali_warn_atapi_dma(adev);

}



/**
@@ -294,6 +320,18 @@ static void ali_lock_sectors(struct ata_device *adev) 


static int ali_check_atapi_dma(struct ata_queued_cmd *qc)

{

	if (!ali_atapi_dma) {

		/* FIXME: pata_ali can't do ATAPI DMA reliably but the

		 * IDE alim15x3 driver can.  I tried lots of things

		 * but couldn't find what the actual difference was.

		 * If you got an idea, please write it to

		 * linux-ide@vger.kernel.org and cc htejun@gmail.com.

		 *

		 * Disable ATAPI DMA for now.

		 */

		return -EOPNOTSUPP;

	}



	/* If its not a media command, its not worth it */

	if (atapi_cmd_type(qc->cdb[0]) == ATAPI_MISC)

		return -EOPNOTSUPP;
@@ -359,6 +397,7 @@ static struct ata_port_operations ali_20_port_ops = { 


	.tf_load	= ata_tf_load,

	.tf_read	= ata_tf_read,

	.check_atapi_dma = ali_check_atapi_dma,

	.check_status 	= ata_check_status,

	.exec_command	= ata_exec_command,

	.dev_select 	= ata_std_dev_select,
@@ -438,6 +477,7 @@ static struct ata_port_operations ali_c5_port_ops = { 
	.check_status 	= ata_check_status,

	.exec_command	= ata_exec_command,

	.dev_select 	= ata_std_dev_select,

	.dev_config	= ali_warn_atapi_dma,



	.freeze		= ata_bmdma_freeze,

	.thaw		= ata_bmdma_thaw,