Hi all, I'm getting weird values from the debugfs file ieee80211/phy0/tsf: the value goes up and down rather randomly and only the lower 24 bits or so seem to ever be used (see below for details). The only thing running on phy0 is a single ap interface (and the monitor companion that hostapd sets up). I was expecting tsf to increase monotonically until all 64 bits had been used. root@OpenWrt:/debug/ieee80211/phy0# dmesg | grep phy0 phy0: Selected rate control algorithm 'minstrel_ht' phy0: Atheros AR9100 MAC/BB Rev:0 AR2133 RF Rev:a2 mem=0xb80c0000, irq=2 root@OpenWrt:/debug/ieee80211/phy0# while sleep 1; do cat tsf; done 0x0000000000059d9b 0x0000000000038fa2 0x00000000000ee67e 0x000000000008121e 0x000000000017752d 0x000000000006438b 0x000000000015a771 0x00000000000d5ea0 0x0000000000085b43 0x0000000000037806 0x000000000001f562 0x0000000000115b03 0x000000000020be55 ^C If you poll tsf really fast it looks a bit like it's running correctly but being reset very often: root@OpenWrt:/debug/ieee80211/phy0# while true; do cat tsf; done ... 0x00000000004b2319 0x00000000004b33f2 0x00000000004b46dc 0x00000000004b578c 0x00000000004b6a89 0x0000000000014435 0x00000000000154a0 0x00000000000167ce 0x000000000001785d ... ^C For a moment I thought it might be the kernel snprintf (on mips) playing a trick on me so I tried the following patch. But the result is the same. diff -urN a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c --- a/net/mac80211/debugfs.c +++ b/net/mac80211/debugfs.c @@ -63,7 +63,8 @@ tsf = drv_get_tsf(local); - snprintf(buf, sizeof(buf), "0x%016llx\n", (unsigned long long) tsf); + snprintf(buf, sizeof(buf), "0x%08lx%08lx\n", + (unsigned long)(tsf >> 32), (unsigned long)tsf); return simple_read_from_buffer(user_buf, count, ppos, buf, 19); } What could be causing this? Because it's not supposed to do this, right? Any insight much appreciated! /Björn -- 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
