[RFC] b43: Fix regression from Bug #14538
From: Larry Finger <hidden>
Date: 2009-11-23 19:55:03
The routine b43_is_hw_radio_enabled() has long been a problem. For PPC architecture with PHY Revision < 3, a read of the register B43_MMIO_HWENABLED_LO will cause a CPU fault unless b43_status() returns a value of 2 (B43_STAT_STARTED) (BUG 14181). Fixing that results in Bug 14538 in which the driver is unable to reassociate after resuming from hibernation because b43_status() returns 0. The correct fix would be to determine why the status is 0; however, I have not yet found why that happens. The correct value is found for my device, which has PHY revision >= 3. Returning TRUE when the PHY revision < 3 and b43_status() returns 0 fixes the regression for 2.6.32. Signed-off-by: Larry Finger <redacted> Tested-by: Christian Casteyde <redacted> --- Index: wireless-testing/drivers/net/wireless/b43/rfkill.c ===================================================================
--- wireless-testing.orig/drivers/net/wireless/b43/rfkill.c
+++ wireless-testing/drivers/net/wireless/b43/rfkill.c@@ -33,9 +33,16 @@ bool b43_is_hw_radio_enabled(struct b43_ & B43_MMIO_RADIO_HWENABLED_HI_MASK)) return 1; } else { - if (b43_status(dev) >= B43_STAT_STARTED && - b43_read16(dev, B43_MMIO_RADIO_HWENABLED_LO) - & B43_MMIO_RADIO_HWENABLED_LO_MASK) + /* To prevent CPU fault on PPC, do not read a register + * unless the interface is started; however, on resume + * for hibernation, this routine is entered early. When + * that happens, unconditionally return TRUE. + */ + if (b43_status(dev) >= B43_STAT_STARTED) { + if (b43_read16(dev, B43_MMIO_RADIO_HWENABLED_LO) + & B43_MMIO_RADIO_HWENABLED_LO_MASK) + return 1; + } else return 1; } return 0;