From: Michael Buesch Date: Tue, 15 Apr 2008 19:13:36 +0000 (+0200) Subject: b43: Add fastpath to b43_mac_suspend() X-Git-Tag: v2.6.26-rc1~1138^2~9^2~14 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=ba380013b681e91e059f95b51002f8d43024b371;p=linux-2.6-omap-h63xx.git b43: Add fastpath to b43_mac_suspend() This adds a fastpath for the common workloads to the MAC suspend flushing. In common workloads the FIFO flush will take between 100 and 200 microseconds. So we want to avoid calling msleep() in the common case, as it will waste over 800 microseconds + scheduler overhead. This fastpath will hit in workloads where only small chunks of data are transmitted (downloading a file) or when a TX rate bigger or equal to 24MBit/s is used when transmitting lots of stuff (iperf). So in the commonly used workloads it will basically always hit. In case the fastpath is not hit, there's no real performance or latency disadvantage from that. And yes, I measured this. So this is not one of these bad Programmer Likeliness Assumptions that are always wrong. ;) Signed-off-by: Michael Buesch Signed-off-by: John W. Linville --- diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c index 345c34bdae9..cf5c046c9fa 100644 --- a/drivers/net/wireless/b43/main.c +++ b/drivers/net/wireless/b43/main.c @@ -2343,6 +2343,13 @@ static void b43_mac_suspend(struct b43_wldev *dev) & ~B43_MACCTL_ENABLED); /* force pci to flush the write */ b43_read32(dev, B43_MMIO_MACCTL); + for (i = 35; i; i--) { + tmp = b43_read32(dev, B43_MMIO_GEN_IRQ_REASON); + if (tmp & B43_IRQ_MAC_SUSPENDED) + goto out; + udelay(10); + } + /* Hm, it seems this will take some time. Use msleep(). */ for (i = 40; i; i--) { tmp = b43_read32(dev, B43_MMIO_GEN_IRQ_REASON); if (tmp & B43_IRQ_MAC_SUSPENDED)