Messages in this thread | | | Date | Thu, 11 Sep 2014 08:32:58 -0400 | From | Peter Hurley <> | Subject | Re: [PATCH 09/16] tty: serial: 8250_dma: Add a TX trigger workaround for AM33xx |
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On 09/11/2014 07:42 AM, Sebastian Andrzej Siewior wrote: > I also need a watchdog timer for TX since it seems that on omap3 the > DMA engine suddenly forgets to continue with DMA…
One difference I noticed between the omap driver and the 8250 driver is the way modem status interrupts are handled.
The omap driver only checks modem status for the UART_IIR_MSI interrupt type. The 8250 driver checks modem status at every interrupt (other than NO_INT).
I think the UART_MSR_DCTS bit always reflects that the CTS input has changed between reads of the MSR _even if auto CTS is on_. So perhaps the hardware is being stopped by uart_handle_cts_change() when auto CTS is on?
Regards, Peter Hurley
[The UPF_HARD_FLOW thing was pretty much just done for omap even though 8250 already had auto CTS/auto RTS. Serial core hardware flow control support needs a redo as drivers have pretty much tacked stuff on randomly.] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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