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@xxxxxxxxx> --- John, this is a bugfix for 2.6.26 Index: wireless-testing/drivers/net/wireless/b43/b43.h =================================================================== --- wireless-testing.orig/drivers/net/wireless/b43/b43.h 2008-06-12 11:42:49.000000000 +0200 +++ wireless-testing/drivers/net/wireless/b43/b43.h 2008-06-12 12:03:29.000000000 +0200 @@ -646,13 +646,12 @@ struct b43_pio { struct b43_pio_rxqueue *rx_queue; }; /* 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]; }; struct b43_stats { Index: wireless-testing/drivers/net/wireless/b43/main.c =================================================================== --- wireless-testing.orig/drivers/net/wireless/b43/main.c 2008-06-12 11:42:49.000000000 +0200 +++ wireless-testing/drivers/net/wireless/b43/main.c 2008-06-12 12:10:11.000000000 +0200 @@ -1142,22 +1142,20 @@ static void b43_jssi_write(struct b43_wl 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) { /* Top half of Link Quality calculation. */ if (dev->noisecalc.calculation_running) return; - dev->noisecalc.channel_at_start = dev->phy.channel; dev->noisecalc.calculation_running = 1; dev->noisecalc.nr_samples = 0; b43_generate_noise_sample(dev); } @@ -1168,15 +1166,22 @@ static void handle_irq_noise(struct b43_ u8 noise[4]; u8 i, j; s32 average; /* 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) goto generate_new; /* Get the noise samples. */ @@ -1211,17 +1216,16 @@ static void handle_irq_noise(struct b43_ if (tmp == 8) average -= 72; else average -= 48; dev->stats.link_noise = average; - drop_calculation: dev->noisecalc.calculation_running = 0; return; } - generate_new: +generate_new: b43_generate_noise_sample(dev); } static void handle_irq_tbtt_indication(struct b43_wldev *dev) { if (b43_is_mode(dev->wl, IEEE80211_IF_TYPE_AP)) { -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
