2010/11/24 Jonathan Guerin <jonathan@xxxxxxxxxxxx>: > On Wed, Nov 24, 2010 at 5:09 AM, Nick Kossifidis <mickflemm@xxxxxxxxx> wrote: >> Â* Extend get_default_sifs/slot_time to include timings for turbo >> Âhalf and quarter rate modes. >> >> Â* AR5210 code for now uses timings already on core clock units >> Âinstead of usecs so rename them (we 'll clean it up later). >> >> ÂSigned-off-by: Nick Kossifidis <mickflemm@xxxxxxxxx> >> --- >> Âdrivers/net/wireless/ath/ath5k/ath5k.h |  24 ++++++++++++-- >> Âdrivers/net/wireless/ath/ath5k/pcu.c  |  52 ++++++++++++++++++++++++-------- >> Âdrivers/net/wireless/ath/ath5k/qcu.c  |  16 +++++---- >> Â3 files changed, 68 insertions(+), 24 deletions(-) >> >> diff --git a/drivers/net/wireless/ath/ath5k/ath5k.h b/drivers/net/wireless/ath/ath5k/ath5k.h >> index 005cad0..e11fc8f 100644 >> --- a/drivers/net/wireless/ath/ath5k/ath5k.h >> +++ b/drivers/net/wireless/ath/ath5k/ath5k.h >> @@ -226,16 +226,16 @@ >> Â#define AR5K_INIT_USEC             39 >> Â#define AR5K_INIT_USEC_TURBO          79 >> Â#define AR5K_INIT_USEC_32           Â31 >> -#define AR5K_INIT_SLOT_TIME          Â396 >> -#define AR5K_INIT_SLOT_TIME_TURBO       Â480 >> +#define AR5K_INIT_SLOT_TIME_CLOCK       Â396 > > This comes out as 9.9us (with a clock multiplier of 40), rather than 9 > - should be 360? > >> +#define AR5K_INIT_SLOT_TIME_TURBO_CLOCK        Â480 >> Â#define AR5K_INIT_ACK_CTS_TIMEOUT       Â1024 > > From a previous post I'd made: > > According to the 802.11-2007 spec document, the ACKTimeout value is > (Section 9.2.8 ACK procedure): > ACKTimeout = aSIFSTime + aSlotTime + aPHY-RX-START-Delay > > From Table 17-15âOFDM PHY characteristics, the values are: > aSIFSTime = 16 > aSlotTime = 9 > aPHY-RX-START-Delay = 25 > > Therefore, ACKTimeout = 50 > > With a value of 1024, the ACKTIMEOUT is actually 25. > >> Â#define AR5K_INIT_ACK_CTS_TIMEOUT_TURBO        Â0x08000800 >> Â#define AR5K_INIT_PROG_IFS           920 >> Â#define AR5K_INIT_PROG_IFS_TURBO        960 >> Â#define AR5K_INIT_EIFS             3440 > > From the 802.11-2007 Spec (9.2.10 DCF timing relations): > The EIFS is derived from the SIFS and the DIFS and the length of time > it takes to transmit an ACK Control frame at the lowest PHY mandatory > rate by the following equation: > EIFS = aSIFSTime + DIFS + ACKTxTime > where ACKTxTime is the time expressed in microseconds required to > transmit an ACK frame, including > preamble, PLCP header and any additional PHY dependent information, at > the lowest PHY mandatory rate. > > So, EIFS = 16 + 32 + 44 (ACKTX @ 24Mbps) = 92 > or 16 + 32 + 60 (ACKTX @ 6Mbps) = 108 > > The current value is 86, which I guess is a nice midpoint, but is > there any reasoning for this value? It should really be set to the > longest value of 108, as an EIFS is only used when we have no > information about a frame because it failed the checksum. > >> Â#define AR5K_INIT_EIFS_TURBO          6880 >> -#define AR5K_INIT_SIFS             560 >> -#define AR5K_INIT_SIFS_TURBO          480 >> +#define AR5K_INIT_SIFS_CLOCK          560 > > This is wrong, when you divide by the clock rate, you get a SIFS of 14, not 16. > > Cheers, > > Jonathan > All _CLOCK variables are left here temporarily until we clean up AR5210 stuff later, i know it's wrong ;-) Check out patch 16 that adds the new set_ifs_intervals, there we set them property, i just left them here so that code can still compile. -- GPG ID: 0xD21DB2DB As you read this post global entropy rises. Have Fun ;-) Nick -- 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
