renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-23 20:53:53 +08:00
Code

b43: avoid PPC fault during resume

Browse Source 
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 <Larry.Finger@lwfinger.net>
Tested-by: Christian Casteyde <casteyde.christian@free.fr>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Larry Finger 2009-11-23 18:40:45 -06:00 committed by John W. Linville
parent 9bf22f2c46
commit c2ff581aca
1 changed files with 8 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/net/wireless/b43/rfkill.c
View File

@ -33,8 +33,14 @@ bool b43_is_hw_radio_enabled(struct b43_wldev *dev)
& 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;
}