[PATCH] iwl3945: increase plcp check threshold

[PATCH] iwl3945: increase plcp check threshold

[Stanislaw Gruszka]

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,

Re: [PATCH] iwl3945: increase plcp check threshold

[wwguy]

Stanislaw,

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?

Wey

Re: [PATCH] iwl3945: increase plcp check threshold

[Stanislaw Gruszka]

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

[PATCH v2] iwl3945: remove plcp check

[Stanislaw Gruszka]

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 removing plcp check 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>
---
v1 -> v2
Instead of tuning threshold remove the check completely

This is minimal fix, without any additional code removal
(what introduce one compile warning). I will remove dead code
after Intel push they current driver split work, to do not
create merge problems now.

Patch also does not apply cleanly on 2.6.35, I will provide
additional -stable patch when this one hit mainline.

diff --git a/drivers/net/wireless/iwlwifi/iwl-3945.c b/drivers/net/wireless/iwlwifi/iwl-3945.c
index 58213e7..5b6932c 100644
--- a/drivers/net/wireless/iwlwifi/iwl-3945.c
+++ b/drivers/net/wireless/iwlwifi/iwl-3945.c
@@ -2734,7 +2734,6 @@ static struct iwl_lib_ops iwl3945_lib = {
 	.isr_ops = {
 		.isr = iwl_isr_legacy,
 	},
-	.check_plcp_health = iwl3945_good_plcp_health,
 
 	.debugfs_ops = {
 		.rx_stats_read = iwl3945_ucode_rx_stats_read,

Re: [PATCH v2] iwl3945: remove plcp check

[wwguy]

On Tue, 2011-02-08 at 23:46 -0800, Stanislaw Gruszka wrote:
> 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 removing plcp check 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>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
> ---
> v1 -> v2
> Instead of tuning threshold remove the check completely
> 
looks good for just minimal changes

Wey