[rt2x00-users] [PATCH 9/9] rt2x00: Fix beaconing on rt2800.

Gertjan van Wingerde gwingerde at gmail.com
Sun May 9 19:41:00 AEST 2010


On 05/09/10 11:21, Ivo Van Doorn wrote:
> On Sat, May 8, 2010 at 11:40 PM, Gertjan van Wingerde
> <gwingerde at gmail.com> wrote:
>> According to the Ralink vendor driver for rt2800 we don't need a full
>> TXD for a beacon but just a TXWI in front of the actual beacon.
>> Fix the rt2800pci and rt2800usb beaconing code accordingly.
>>
>> Signed-off-by: Gertjan van Wingerde <gwingerde at gmail.com>
>> ---
>>  drivers/net/wireless/rt2x00/rt2800pci.c |   17 +++++++++--------
>>  drivers/net/wireless/rt2x00/rt2800usb.c |   14 ++++++--------
>>  2 files changed, 15 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/net/wireless/rt2x00/rt2800pci.c b/drivers/net/wireless/rt2x00/rt2800pci.c
>> index 80c6768..7d4778d 100644
>> --- a/drivers/net/wireless/rt2x00/rt2800pci.c
>> +++ b/drivers/net/wireless/rt2x00/rt2800pci.c
>> @@ -682,7 +682,6 @@ static void rt2800pci_write_beacon(struct queue_entry *entry,
>>                                   struct txentry_desc *txdesc)
>>  {
>>        struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;
>> -       struct skb_frame_desc *skbdesc = get_skb_frame_desc(entry->skb);
>>        unsigned int beacon_base;
>>        u32 reg;
>>
>> @@ -695,15 +694,17 @@ static void rt2800pci_write_beacon(struct queue_entry *entry,
>>        rt2800_register_write(rt2x00dev, BCN_TIME_CFG, reg);
>>
>>        /*
>> -        * Write entire beacon with descriptor to register.
>> +        * Add the TXWI for the beacon to the skb.
>> +        */
>> +       rt2800_write_txwi(entry->skb, txdesc);
>> +       skb_push(entry->skb, TXWI_DESC_SIZE);
> 
> This looks quite suspicious...
> First writing into the SKB and only then making room for it?
> Perhaps we should make sure rt2800_write_txwi demands the
> room is already added (or it calls skb_push itself).
> 

Yep, I wasn't too happy with this as well. It's on my TODO-list to fix that up, but that
requires more restructuring of the common code.
For the sake of keeping this patch small I kept it this way, and I'm already working on
follow-up patches to clean the skb handling up, so that we don't have to fiddle around
with the skb->data pointer anymore when creating descriptors and TXWI's.

---
Gertjan.




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