On Wed, 10 Jan 2024 20:20:39 +0000 : Abhishek Chauhan (ABC) wrote: > Qualcomm had similar discussions with respect to enabling of TBS for a > particular queue. > We had similar discussion on these terms yesterday with Redhat. Adding > Andrew from Redhat here > > What we discovered as part of the discussions is listed below. > > 1. Today upstream stmmac code is designed in such a way that TBS flag is put > as part of queue configurations(see below snippet) and as well know that > stmmac queue configuration comes from the dtsi file. > > //ndo_open => stmmac_open > int tbs_en = priv->plat->tx_queues_cfg[chan].tbs_en;(comes from > tx_queues_cfg) > > /* Setup per-TXQ tbs flag before TX descriptor alloc */ tx_q->tbs |= tbs_en ? > STMMAC_TBS_AVAIL : 0; > > 2. There is a no way to do this dynamically from user space because we don't > have any API exposed which can do it from user space and also TBS rely on > special descriptors aka enhanced desc this cannot be done run time and > stmmac has to be aware of it before we do DMA/MAC/MTL start. To do this > dynamically would only mean stopping DMA/MAC/MTL realloc resources for > enhanced desc and the starting MAC/DMA/MTL. This means we are disrupting > other traffic(By stopping MAC block). > > 3. I dont think there is a way we can enable this dynamically today. I would like > upstream community to share your thoughts as well. > > 4. I agree with Rohan's patch here and want upstream community to accept it. > This will allow use to configure the queues where TBS needs to be enabled as > hardcoding in the code unless upstream has better way to this using > userspace. > > Please let us know if you think otherwise. > > Hi Abhishek, Thanks for bringing this to discussion and a better explanation from your side. I agree with you. Best Regards, Rohan
