diff options
| author | Michael Buesch <mb@bu3sch.de> | 2008-06-14 23:00:14 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-06-21 22:24:55 -0700 |
| commit | f9cb92ec51b8700247c3aa560b31ba9885a33e73 (patch) | |
| tree | 06b0cecc82203998d97cf2ef894f517521f9932c | |
| parent | 226028e4f78348aa948b1422bda1ede029228d2e (diff) | |
b43: Fix noise calculation WARN_ON
commit 98a3b2fe435ae76170936c14f5c9e6a87548e3ef upstream.
This removes a WARN_ON that is responsible for the following koops:
http://www.kerneloops.org/searchweek.php?search=b43_generate_noise_sample
The comment in the patch describes why it's safe to simply remove
the check.
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/net/wireless/b43/b43.h | 1 | ||||
| -rw-r--r-- | drivers/net/wireless/b43/main.c | 16 |
2 files changed, 10 insertions, 7 deletions
diff --git a/drivers/net/wireless/b43/b43.h b/drivers/net/wireless/b43/b43.h index 44ebdea7c955..b14087b68852 100644 --- a/drivers/net/wireless/b43/b43.h +++ b/drivers/net/wireless/b43/b43.h @@ -596,7 +596,6 @@ struct b43_dma { /* Context information for a noise calculation (Link Quality). */ struct b43_noise_calculation { - u8 channel_at_start; bool calculation_running; u8 nr_samples; s8 samples[8][4]; diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c index 6966eec666e2..b4a20423afeb 100644 --- a/drivers/net/wireless/b43/main.c +++ b/drivers/net/wireless/b43/main.c @@ -1027,7 +1027,6 @@ static void b43_generate_noise_sample(struct b43_wldev *dev) b43_jssi_write(dev, 0x7F7F7F7F); b43_write32(dev, B43_MMIO_MACCMD, b43_read32(dev, B43_MMIO_MACCMD) | B43_MACCMD_BGNOISE); - B43_WARN_ON(dev->noisecalc.channel_at_start != dev->phy.channel); } static void b43_calculate_link_quality(struct b43_wldev *dev) @@ -1036,7 +1035,6 @@ static void b43_calculate_link_quality(struct b43_wldev *dev) if (dev->noisecalc.calculation_running) return; - dev->noisecalc.channel_at_start = dev->phy.channel; dev->noisecalc.calculation_running = 1; dev->noisecalc.nr_samples = 0; @@ -1053,9 +1051,16 @@ static void handle_irq_noise(struct b43_wldev *dev) /* Bottom half of Link Quality calculation. */ + /* Possible race condition: It might be possible that the user + * changed to a different channel in the meantime since we + * started the calculation. We ignore that fact, since it's + * not really that much of a problem. The background noise is + * an estimation only anyway. Slightly wrong results will get damped + * by the averaging of the 8 sample rounds. Additionally the + * value is shortlived. So it will be replaced by the next noise + * calculation round soon. */ + B43_WARN_ON(!dev->noisecalc.calculation_running); - if (dev->noisecalc.channel_at_start != phy->channel) - goto drop_calculation; *((__le32 *)noise) = cpu_to_le32(b43_jssi_read(dev)); if (noise[0] == 0x7F || noise[1] == 0x7F || noise[2] == 0x7F || noise[3] == 0x7F) @@ -1096,11 +1101,10 @@ static void handle_irq_noise(struct b43_wldev *dev) average -= 48; dev->stats.link_noise = average; - drop_calculation: dev->noisecalc.calculation_running = 0; return; } - generate_new: +generate_new: b43_generate_noise_sample(dev); } |