Tony Chuang <yhchuang@xxxxxxxxxxx> writes: > // Add Johannes for commenting on adding another nl80211 commands > > Kalle Valo <kvalo@xxxxxxxxxxxxxx> writes:> > >> Tony Chuang <yhchuang@xxxxxxxxxxx> writes: >> >> > Kalle Valo <kvalo@xxxxxxxxxxxxxx> writes: >> > >> >> <yhchuang@xxxxxxxxxxx> writes: >> >> >> >> > From: Yan-Hsuan Chuang <yhchuang@xxxxxxxxxxx> >> >> > >> >> > It is useful to fix the bit rate of TX packets. For example, if >> >> > someone is measuring the TX power, or debugging with the issues >> >> > of the TX throughput on the field. >> >> > >> >> > To set the value of fixed rate, one should input corresponding >> >> > desc rate index (ex, 0x0b for DESC_RATE54M to fix at 54 Mbps). >> >> > Set a value larger than DESC_RATE_MAX will disable fix rate, so >> >> > the rate adaptive mechanism can resume to work. >> >> > >> >> > Example, >> >> > To fix rate at MCS 1: >> >> > echo 0x0d > /sys/kernel/debug/ieee80211/phy0/rtw88/fix_rate >> >> > >> >> > To not to fix rate: >> >> > echo 0xff > /sys/kernel/debug/ieee80211/phy0/rtw88/fix_rate >> >> > >> >> > To know which rate was fixed at: >> >> > cat /sys/kernel/debug/ieee80211/phy0/rtw88/fix_rate >> >> > >> >> > Signed-off-by: Yan-Hsuan Chuang <yhchuang@xxxxxxxxxxx> >> >> >> >> No way, debugfs is not a method for working around nl80211 and doing >> >> whatever idea you come up with. The goal is that we have a generic >> >> nl80211 command for all generic actions, like this one. And I think we >> >> already have an nl80211 command for fixing the tx rate, right? >> >> >> > >> > No, as I can see, there's no suitable nl80211 command that can achieve >> > what I want. If you are saying about >> NL80211_CMD_SET_TX_BITRATE_MASK, >> > it's used to allow some rates. But actually the firmware has its own rate >> > adaptive mechanism, so mask out the other rates does not mean the rate >> > left will be chosen. Moreover, the hardware will choose a lower bit rate >> > when retry, then the TX rate is not fixed at all. So the debugfs can disable >> > the firmware's RA mechanism, also disable the TX rate fall back when retry. >> > Both of them cannot be done by setting TX bitrate mask. >> >> I'm confused, here you talk about firmware implementation etc but I'm >> just talking about replacing the fix_rate debugfs file to an nl80211 >> command (for providing the fix_rate value). Can you clarify more why you >> think nl80211 is not suitable? > > Oops, I thought that you wanted me to use the existing nl80211 > command. Either use an existing nl80211 command or add a new one if needed. For me most important is that we don't add hacks to debugfs just for avoiding using nl80211. > Now I know that you think we can add a new nl80211 command to help > drivers to fix the TX bitrate if necessary. If adding another nl80211 > command for that is acceptable, I can work on this. But I need > Johannes's comment if it's better to add a new nl80211 command or to > expand the existing command (ex. NL80211_CMD_SET_TX_BITRATE_MASK). _Why_ is NL80211_CMD_SET_TX_BITRATE_MASK not suitable for you? You keep saying that but I have still figured out why exactly you think so. Please clarify this in detail. > It looks like that adding a new nl80211 command will be better for me > as expanding the existing one would have great impact on the already > distributed drivers/user-tools. What kind of great impact are you talking about? Please be specific so that we don't need to guess. -- https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
