pcmcia/yenta: guide users in case of problems with O2-bridges

Some cards need the speedups on, some need them off. As we can't detect
this reliably, at least give the users a hint how to tweak the system.

Reported-by: David Bluecame <david.bluecame@gmail.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

drivers/pcmcia/o2micro.h

@@ -153,14 +153,14 @@ static int o2micro_override(struct yenta_socket *socket)
 
 		if (use_speedup) {
 			dev_info(&socket->dev->dev,
-				"O2: enabling read prefetch/write burst\n");
+				"O2: enabling read prefetch/write burst. If you experience problems or performance issues, use the yenta_socket parameter 'o2_speedup=off'\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);
 		} else {
 			dev_info(&socket->dev->dev,
-				"O2: disabling read prefetch/write burst\n");
+				"O2: disabling read prefetch/write burst. If you experience problems or performance issues, use the yenta_socket parameter 'o2_speedup=on'\n");
 			config_writeb(socket, O2_RESERVED1,
 				      a & ~(O2_RES_READ_PREFETCH | O2_RES_WRITE_BURST));
 			config_writeb(socket, O2_RESERVED2,