Re: serial: imx: disable DMA for RS-485 on i.MX6 SMP
From: Clemens Gruber
Date: Sun Jul 02 2017 - 16:48:25 EST
On Tue, Jun 20, 2017 at 08:49:28PM -0300, Fabio Estevam wrote:
> Hi Clemens,
> On Tue, Jun 20, 2017 at 1:13 PM, Fabio Estevam <festevam@xxxxxxxxx> wrote:
> > The subject gives the impression that the DMA will only be disabled
> > for RS485, but the impact of this change is wider.
> > For example: if I have a mx6q system with a Bluetooth serial
> > connection I can no longer use DMA with your change applied.
> > Ideally we should fix the RS485 DMA bug. If that is not possible, then
> > at least we need to restrict this change to the RS485 case.
> > Maybe we need to pass "linux,rs485-enabled-at-boot-time" in device
> > tree and then use this property to deceide if DMA will be enabled or
> > not:
> > if (!uart_console(port) && !sport->dma_is_inited && !sport->rs485_enabled)
> Could you please test the two attached patches and see if it solves the issue?
> Unfortunately I no longer have access to the RS485 half-duplex board.
> Just make sure to pass 'linux,rs485-enabled-at-boot-time' in your
> device tree, thanks.
The two patches work for me!
You can add my Tested-by tag if/when you submit them.
Tested-by: Clemens Gruber <clemens.gruber@xxxxxxxxxxxx>