* Vignesh R <vigneshr@xxxxxx> [170118 04:04]: > > > On Wednesday 18 January 2017 04:55 AM, Tony Lindgren wrote: > > * Vignesh R <vigneshr@xxxxxx> [170117 02:06]: > >> > >> > >> On Tuesday 17 January 2017 11:36 AM, Vignesh R wrote: > >>> > >>> > >>> On Friday 13 January 2017 11:50 PM, Tony Lindgren wrote: > >>>> * Vignesh R <vigneshr@xxxxxx> [170113 00:03]: > >>>>> This patch series re enables DMA support for UART 8250_omap driver. > >>>>> > >>>>> Tested on AM335x, AM437x that use EDMA and OMAP5 and DRA74 EVM with > >>>>> SDMA. > >>>> > >>>> Is 8250_omap serial console working for you on omap5 in general? > >>>> > >>>> I've noticed that it's really unresponsive for me as if the FIFO > >>>> interrupt was not working. For example logging in might take several > >>>> attempts and a long time with each character showing up much later > >>>> after some timeout. > >>>> > >>> > >>> Yes, I did face the same issue on omap5 using 8250_omap driver for > >>> console. Looks like this bug has existed all along. > >>> > >> > >> This looks a separate issue, I don't see any errata specific errata wrt > >> UART on OMAP5. I will try to debug further. > > > > OK maybe it's something configured or not configured by the bootloader > > that we're missing in the Linux driver? > > > > omap-serial uses a UART RX FIFO trigger of 1 byte whereas 8250_omap > driver uses a RX FIFO trigger of 48 bytes. If less than 48 bytes is > received then RX Timeout interrupt is raised which will help the driver > to flush the FIFO. It seems like RX timeout does not seem to bring out > UART IP from idle state on OMAP5. > > I have posted a fix based on what is done for DRA7 in hwmod code: > http://lists.infradead.org/pipermail/linux-arm-kernel/2017-January/480619.html OK great, thanks for fixing that! Will give it a try a bit later today. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
