1 files changed, 27 insertions, 7 deletions

diff --git a/drivers/pcmcia/o2micro.h b/drivers/pcmcia/o2micro.h
index b1f6e3d9ee06..a234ce1967a3 100644
--- a/drivers/pcmcia/o2micro.h
+++ b/drivers/pcmcia/o2micro.h
@@ -120,11 +120,16 @@
 #define  O2_MODE_E_LED_OUT      0x08
 #define  O2_MODE_E_SKTA_ACTV    0x10
 
+#define O2_RESERVED1            0x94
+#define O2_RESERVED2            0xD4
+#define O2_RES_READ_PREFETCH    0x02
+#define O2_RES_WRITE_BURST      0x08
+
 static int o2micro_override(struct yenta_socket *socket)
 {
         /*
-         * 'reserved' register at 0x94/D4. chaning it to 0xCA (8 bit) enables
-         * read prefetching which for example makes the RME Hammerfall DSP
+         * 'reserved' register at 0x94/D4. allows setting read prefetch and write
+         * bursting. read prefetching for example makes the RME Hammerfall DSP
          * working. for some bridges it is at 0x94, for others at 0xD4. it's
          * ok to write to both registers on all O2 bridges.
          * from Eric Still, 02Micro.
@@ -132,20 +137,35 @@ static int o2micro_override(struct yenta_socket *socket)
         u8 a, b;
 
         if (PCI_FUNC(socket->dev->devfn) == 0) {
-                a = config_readb(socket, 0x94);
-                b = config_readb(socket, 0xD4);
+                a = config_readb(socket, O2_RESERVED1);
+                b = config_readb(socket, O2_RESERVED2);
 
                 printk(KERN_INFO "Yenta O2: res at 0x94/0xD4: %02x/%02x\n", a, b);
 
                 switch (socket->dev->device) {
+                /*
+                 * older bridges have problems with both read prefetch and write
+                 * bursting depending on the combination of the chipset, bridge
+                 * and the cardbus card. so disable them to be on the safe side.
+                 */
+                case PCI_DEVICE_ID_O2_6729:
+                case PCI_DEVICE_ID_O2_6730:
+                case PCI_DEVICE_ID_O2_6812:
                 case PCI_DEVICE_ID_O2_6832:
-                        printk(KERN_INFO "Yenta O2: old bridge, not enabling read prefetch / write burst\n");
+                case PCI_DEVICE_ID_O2_6836:
+                        printk(KERN_INFO "Yenta O2: old bridge, disabling read prefetch/write burst\n");
+                        config_writeb(socket, O2_RESERVED1,
+                                      a & ~(O2_RES_READ_PREFETCH | O2_RES_WRITE_BURST));
+                        config_writeb(socket, O2_RESERVED2,
+                                      b & ~(O2_RES_READ_PREFETCH | O2_RES_WRITE_BURST));
                         break;
 
                 default:
                         printk(KERN_INFO "Yenta O2: enabling read prefetch/write burst\n");
-                        config_writeb(socket, 0x94, a | 0x0a);
-                        config_writeb(socket, 0xD4, b | 0x0a);
+                        config_writeb(socket, O2_RESERVED1,
+                                      a | O2_RES_READ_PREFETCH | O2_RES_WRITE_BURST);
+                        config_writeb(socket, O2_RESERVED2,
+                                      b | O2_RES_READ_PREFETCH | O2_RES_WRITE_BURST);
                 }
         }