patch-2.3.4 linux/drivers/block/ns87415.c

• Lines: 26
• Date: Sat May 29 11:09:04 1999
• Orig file: v2.3.3/linux/drivers/block/ns87415.c
• Orig date: Fri May 14 18:55:14 1999

diff -u --recursive --new-file v2.3.3/linux/drivers/block/ns87415.c linux/drivers/block/ns87415.c
@@ -49,8 +49,25 @@
 	new = use_dma ? ((new & ~other) | bit) : (new & ~bit);
 
 	if (new != *old) {
+		unsigned char stat;
+
+		/*
+		 * Don't change DMA engine settings while Write Buffers
+		 * are busy.
+		 */
+		(void) pci_read_config_byte(dev, 0x43, &stat);
+		while (stat & 0x03) {
+			udelay(1);
+			(void) pci_read_config_byte(dev, 0x43, &stat);
+		}
+
 		*old = new;
 		(void) pci_write_config_dword(dev, 0x40, new);
+
+		/*
+		 * And let things settle...
+		 */
+		udelay(10);
 	}
 
 	__restore_flags(flags);	/* local CPU only */