Hi Arend, This patch has the following goal. To implement Transmission Power Control (TPC) in the mac80211 subsystem, I remove the STA pointer from the ieee_tx_info structure to gain free mem for TPC annotation and I put the sta on the stack to pass it to each driver function in the tx-path. The broadcom brcmsmac is the only driver where the ieee_tx_info is somewhat stored and therefore the sta point is not as straight removable as for the other drivers. This patch resolved that issue. Please have a look at my recent patch [PATCH] mac80211: Add transmit power control support (TPC) where I have included this one again with the full story in the code. Greetings Thomas Arend van Spriel schrieb: > On 07/06/2012 09:37 PM, John W. Linville wrote: >> On Fri, Jun 29, 2012 at 11:04:16AM -0400, thomas wrote: >>> Johannes Berg schrieb: >>> >>>> On Fri, 2012-06-29 at 05:56 -0700, Thomas Huehn wrote: >>>>> brcmsmac uses info->control.sta while doing ampdu aggregation. This patch >>>>> changes the usage of the structure info->control.sta, as it is going to be >>>>> removed soon from struct ieee80211_tx_info. This patch is a pre-requisit in >>>>> order to add transmission power control (TPC) to the mac80211 subsystem. >>>>> >>>>> Suggested-by: Felix Fietkau <nbd@xxxxxxxxxxx> >>>>> Signed-off-by: Thomas Huehn <thomas@xxxxxxxxxxxxxxxxxxxxxxx> >>>>> --- >>>>> Change sequence of overwriting data. Thx to Johannes. >>>> >>>>> @@ -665,7 +665,7 @@ brcms_c_sendampdu(struct ampdu_info *ampdu, struct brcms_txq_info *qi, >>>>> u8 plcp0, plcp3, is40, sgi; >>>>> struct ieee80211_sta *sta; >>>>> >>>>> - sta = tx_info->control.sta; >>>>> + sta = tx_info->rate_driver_data[0]; >>>> Are you sure it actually works now? >>> >>> From locking at the code, sta is never used after it gets overridden. >>> The brcmsmac driver does not use the vif pointer at all. I asked Felix >>> to double check as I do not have a Broadcom device over here. >>> >>> Bye Thomas >> Any comments on this one from the Broadcom camp? >> > > Hi John, > > Just applied the patch to have a closer look at the changes, but I am > missing details on the whole story. I see tx_info->rate_driver_data[0] > being set in the tx callback and reset to NULL in some other path which > I believe is only called upon tid or sta removal so it does not make > sense to me. > > I have pushed the patch to our internal review server as I would like > some co-workers to have a look. If anyone can provide any more details > what this patch is trying to solve, please do. > > Gr. AvS > > -- > 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 -- 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
