Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes

[Peter Hurley]

On 04/11/2016 01:18 AM, John Ogness wrote:
> On 2016-04-05, Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> wrote:
>> On 03/31/2016 01:41 AM, John Ogness wrote:
>>> It has been observed that the TX-DMA can stall
>>
>> Does this happen on any other OMAP part besides am335x?
>> I looked back over the LKML history of this and didn't see
>> any other design implicated in this problem.
> 
> I just ran the tests again using 4.6-rc2. I am able to reproduce the
> dma-tx stall with am335x/edma and dra7/sdma.

I thought we already established sdma was not to be used since
the hardware does not actually support pausing without data loss.

http://www.spinics.net/lists/linux-serial/msg18503.html


So I'm wondering if we're carrying all this extra DMA complexity
and workarounds for just am335x?


> Note: To achieve the stall, both the delayed_restore and the
>       rx_dma_broken features of the mainline 8250_omap driver needed to
>       be removed.
> 
> John Ogness
>