Re: [PATCH] iwl3945: increase plcp check threshold

[Stanislaw Gruszka <sgruszka@redhat.com>]

On Tue, Feb 08, 2011 at 07:47:20AM -0800, wwguy wrote:
> On Tue, 2011-02-08 at 01:04 -0800, Stanislaw Gruszka wrote:
> > iwl3945: increase plcp check threshold
> > 
> > Patch fixes:
> > https://bugzilla.redhat.com/show_bug.cgi?id=654599
> > 
> > Many users report very low speed problem on 3945 devices,
> > this patch fixes problem, but only for some of them.
> > 
> > For unknown reason, sometimes after hw scanning, device is not able
> > to receive frames at high rate. Since plcp health check may request
> > hw scan to "reset radio", performance problem start to be observable
> > after update kernel to .35, where plcp check was introduced.
> > 
> > Bug reporter confirmed that increase plcp check threshold fixed
> > problem for him.
> > 
> > Reported-and-tested-by: SilvioTO <silviotoya@yahoo.it>
> > Cc: stable@kernel.org  # 2.6.35+
> > Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
> > ---
> > Patch is oneliner, but does not apply on older kernel versions,
> > I will provide -stable patches when fix will land in mainline
> > 
> > diff --git a/drivers/net/wireless/iwlwifi/iwl-3945.c b/drivers/net/wireless/iwlwifi/iwl-3945.c
> > index 58213e7..27faa5e 100644
> > --- a/drivers/net/wireless/iwlwifi/iwl-3945.c
> > +++ b/drivers/net/wireless/iwlwifi/iwl-3945.c
> > @@ -2775,7 +2775,7 @@ static struct iwl_base_params iwl3945_base_params = {
> >  	.use_isr_legacy = true,
> >  	.led_compensation = 64,
> >  	.broken_powersave = true,
> > -	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
> > +	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_THRESHOLD_MAX,
> >  	.wd_timeout = IWL_DEF_WD_TIMEOUT,
> >  	.max_event_log_size = 512,
> >  	.tx_power_by_driver = true,
> 
> Do you see any help for 3945 with plcp checking at all?

Not really, I see only demage :-)

Ok, if we argree to remove plcp check from 3945 at all, I will
repost with slightly different patch for fix problem on stable.

Stanislaw