--- sata_sil.c	2007-04-26 05:08:32.000000000 +0200
+++ sata_sil.c	2007-05-04 20:06:03.000000000 +0200
@@ -43,10 +43,11 @@
 #include <linux/interrupt.h>
 #include <linux/device.h>
 #include <scsi/scsi_host.h>
+#include <scsi/scsi_cmnd.h>
 #include <linux/libata.h>
 
 #define DRV_NAME	"sata_sil"
-#define DRV_VERSION	"2.1"
+#define DRV_VERSION	"2.1a"
 
 enum {
 	SIL_MMIO_BAR		= 5,
@@ -121,6 +122,7 @@
 static irqreturn_t sil_interrupt(int irq, void *dev_instance);
 static void sil_freeze(struct ata_port *ap);
 static void sil_thaw(struct ata_port *ap);
+static int sil_check_atapi_dma(struct ata_queued_cmd *qc);
 
 
 static const struct pci_device_id sil_pci_tbl[] = {
@@ -196,6 +198,7 @@
 	.tf_read		= ata_tf_read,
 	.check_status		= ata_check_status,
 	.exec_command		= ata_exec_command,
+	.check_atapi_dma	= sil_check_atapi_dma,
 	.dev_select		= ata_std_dev_select,
 	.post_set_mode		= sil_post_set_mode,
 	.bmdma_setup            = ata_bmdma_setup,
@@ -289,6 +292,22 @@
 module_param(slow_down, int, 0444);
 MODULE_PARM_DESC(slow_down, "Sledgehammer used to work around random problems, by limiting commands to 15 sectors (0=off, 1=on)");
 
+static int sil_check_atapi_dma(struct ata_queued_cmd *qc)
+{
+	/* limit zero data size atapi commands to pio as certain sil */
+	/* chips seem to have trouble to perform dma for these commands */
+	if ( (qc->scsicmd != NULL) &&
+             (qc->scsicmd->sc_data_direction != DMA_NONE) &&
+	     (qc->nbytes == 0) )
+	{
+		/* do not allow dma */
+		return -1;
+	}
+
+	/* allow dma */
+	return 0;
+}
+
 
 static unsigned char sil_get_device_cache_line(struct pci_dev *pdev)
 {