On Wed, Jul 13, 2022 at 2:43 PM Vamshi Gajjela <vamshigajjela@xxxxxxxxxx> wrote: > > From: VAMSHI GAJJELA <vamshigajjela@xxxxxxxxxx> > > With PSLVERR_RESP_EN parameter set to 1, the device generates an error > response when an attempt to read an empty RBR with FIFO enabled. > > This happens when LCR writes are ignored when UART is busy. > dw8250_check_lcr() in retries to update LCR, invokes dw8250_force_idle() > to clear and reset FIFO and eventually reads UART_RX causing the error. > > Avoid this by not reading RBR/UART_RX when no data is available. Thanks for an update! My comments below. ... > + /* > + * With PSLVERR_RESP_EN parameter set to 1, the device generates an > + * error response when an attempt to read empty RBR with FIFO enabled. an empty > + */ > + lsr = p->serial_in(p, UART_LSR); I have just noticed that you do it independently on FIFO enablement. > + if ((up->fcr & UART_FCR_ENABLE_FIFO) && !(lsr & UART_LSR_DR)) > + return; I would recommend to move it inside the conditional if (fcr & FIFO) { lsr = ... if (!(lsr &)) return; } -- With Best Regards, Andy Shevchenko