Re: [PATCH] rt2x00: rt2800lib: disable HT40 for now as it causes reception problems

[Gertjan van Wingerde <gwingerde@gmail.com>]

On 04/23/10 15:05, Helmut Schaa wrote:
> Disable HT40 support for now as it causes rx problems with HT40 capable
> 11n APs (when mac80211 enables HT40, rx is completely disfunctional).
> 
> Once the rt2800 HT code is capable of using HT40 we should enable the
> flag again.
> 
> I only tested this patch with a rt305x SoC device, nevertheless the
> patch disables HT40 also on PCI and USB rt2800 devices.
> 
> Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>

I can confirm that this also helps for PCI and USB devices.
With this patch applied all my rt28xx and rt30xx based devices starting working correctly.

So, definately,

Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>

> ---
> 
> Using this patch I was able to associate a rt305x SoC device with my 11n
> capable AP using WPA and the connection basically works although I see lots
> of retried frames when sniffing the wireless traffic.
> 
> If someone already had success with rt2800 and HT40 capable APs we should
> consider to only conditionally unset the HT40 flag for 305x SoC devices.
> 
>  drivers/net/wireless/rt2x00/rt2800lib.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/net/wireless/rt2x00/rt2800lib.c b/drivers/net/wireless/rt2x00/rt2800lib.c
> index 2648f31..aa02ff6 100644
> --- a/drivers/net/wireless/rt2x00/rt2800lib.c
> +++ b/drivers/net/wireless/rt2x00/rt2800lib.c
> @@ -2318,8 +2318,11 @@ int rt2800_probe_hw_mode(struct rt2x00_dev *rt2x00dev)
>  	else
>  		spec->ht.ht_supported = false;
>  
> +	/*
> +	 * Don't set IEEE80211_HT_CAP_SUP_WIDTH_20_40 for now as it causes
> +	 * reception problems with HT40 capable 11n APs
> +	 */
>  	spec->ht.cap =
> -	    IEEE80211_HT_CAP_SUP_WIDTH_20_40 |
>  	    IEEE80211_HT_CAP_GRN_FLD |
>  	    IEEE80211_HT_CAP_SGI_20 |
>  	    IEEE80211_HT_CAP_SGI_40 |