Hi Ulrich-san, > From: Ulrich Hecht, Sent: Monday, April 12, 2021 5:04 PM > > > On 04/12/2021 8:23 AM Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote: > > Hmm, when we use HSCIF with 10 bits, 3000000 baud and 128 bytes FIFO, > > the rx_timeout value will be set to 1536 (us). So, if we set rx_timeout > > to 20000 (us) as a minimum value, the sh-sci' behavior will be back to > > non hrtimer support, IIUC. > > > > Perhaps, describing uart_update_timeout() and the jiffies value of > > uart_port->timeout with 115200 baud here may cause misreading?? > > I didn't understand the purpose of uart_port->timeout yet thought. > > But, at least, the current driver uses hrtimer to improve latency > > for HSCIF, the driver should not set 20000 (us) as a minimum value. > > Not having looked at this stuff in a while, I was under the impression that the rx timeout is an error condition, when > it is in fact part of normal (DMA) operation. I think it was indeed the reference to uart_update_timeout() that threw > me off... I think so... > So if my understanding is correct now, we should scrap the minimum timeout code entirely because the condition it is supposed > to prevent cannot occur any longer due to the switch to hrtimers. Did I get that right? Yes, this is the same as my understanding. Best regards, Yoshihiro Shimoda > CU > Uli
