Return-path: Received: from hrndva-omtalb.mail.rr.com ([71.74.56.125]:36809 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752570AbZKXAkk (ORCPT ); Mon, 23 Nov 2009 19:40:40 -0500 Date: Mon, 23 Nov 2009 18:40:45 -0600 From: Larry Finger To: John W Linville , Michael Buesch Cc: casteyde.christian@free.fr, bcm43xx-dev@lists.berlios.de, linux-wireless@vger.kernel.org Subject: [PATCH] b43: Fix regression from Bug #14538 Message-ID: <4b0b2b8d.xO2YhnfbtfQkOOaq%Larry.Finger@lwfinger.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-wireless-owner@vger.kernel.org List-ID: 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. This patch fixes the problem in Red Hat Bugzilla #538523. Signed-off-by: Larry Finger Tested-by: Christian Casteyde --- John, Your suggested change was a good one and has been implemented. This is 2.6.32 material and should be backported to stable; however, it may not apply cleanly. Should I make it Cc: stable, or submit it to GregKH in the proper form once it is committed to mainline? Larry --- 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 @@ -33,8 +33,14 @@ 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) + /* 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) + return 1; + if (b43_read16(dev, B43_MMIO_RADIO_HWENABLED_LO) & B43_MMIO_RADIO_HWENABLED_LO_MASK) return 1; }