b43: fall back gracefully to PIO mode after fatal DMA errors

This makes the b43 driver just automatically fall back to PIO mode when
DMA doesn't work.

The driver already told the user to do it, so rather than have the user
reload the module with a new flag, just make the driver do it
automatically. We keep the message as an indication that something is
wrong, but now just automatically fall back to the hopefully working PIO
case.

(Some post-2.6.33 merge fixups by Larry Finger <Larry.Finger@lwfinger.net>
and yours truly... -- JWL)

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 8 insertions, 6 deletions

diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index 8f7a8c0ec27d..16580d0d3a02 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -107,9 +107,9 @@ int b43_modparam_verbose = B43_VERBOSITY_DEFAULT;
 module_param_named(verbose, b43_modparam_verbose, int, 0644);
 MODULE_PARM_DESC(verbose, "Log message verbosity: 0=error, 1=warn, 2=info(default), 3=debug");
 
-static int modparam_pio;
-module_param_named(pio, modparam_pio, int, 0444);
-MODULE_PARM_DESC(pio, "enable(1) / disable(0) PIO mode");
+int b43_modparam_pio = B43_PIO_DEFAULT;
+module_param_named(pio, b43_modparam_pio, int, 0644);
+MODULE_PARM_DESC(pio, "Use PIO accesses by default: 0=DMA, 1=PIO");
 
 static const struct ssb_device_id b43_ssb_tbl[] = {
         SSB_DEVICE(SSB_VENDOR_BROADCOM, SSB_DEV_80211, 5),
@@ -1804,8 +1804,9 @@ static void b43_do_interrupt_thread(struct b43_wldev *dev)
                                dma_reason[4], dma_reason[5]);
                         b43err(dev->wl, "This device does not support DMA "
                                "on your system. Please use PIO instead.\n");
-                        b43err(dev->wl, "Unload the b43 module and reload "
-                               "with 'pio=1'\n");
+                        /* Fall back to PIO transfers if we get fatal DMA errors! */
+                        dev->use_pio = 1;
+                        b43_controller_restart(dev, "DMA error");
                         return;
                 }
                 if (merged_dma_reason & B43_DMAIRQ_NONFATALMASK) {
@@ -4357,7 +4358,7 @@ static int b43_wireless_core_init(struct b43_wldev *dev)
 
         if ((dev->dev->bus->bustype == SSB_BUSTYPE_PCMCIA) ||
             (dev->dev->bus->bustype == SSB_BUSTYPE_SDIO) ||
-            modparam_pio) {
+            dev->use_pio) {
                 dev->__using_pio_transfers = 1;
                 err = b43_pio_init(dev);
         } else {
@@ -4824,6 +4825,7 @@ static int b43_one_core_attach(struct ssb_device *dev, struct b43_wl *wl)
         if (!wldev)
                 goto out;
 
+        wldev->use_pio = b43_modparam_pio;
         wldev->dev = dev;
         wldev->wl = wl;
         b43_set_status(wldev, B43_STAT_UNINIT);