Messages in this thread | | | Date | Thu, 7 May 2015 17:54:31 -0300 | Subject | Re: [PATCH] serial: imx: Revert "initialized DMA w/o HW flow enabled" | From | Fabio Estevam <> |
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On Thu, May 7, 2015 at 5:24 PM, Sebastian Andrzej Siewior <sebastian@breakpoint.cc> wrote: > From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > > This basically reverts commit 068500e08dc8 ("serial: imx: initialized > DMA w/o HW flow enabled") simply because it does not work as expected > without additional magic which I am not aware of. The DMA mode is only > used for non-console UARTs so the "standard" boot test won't notice this. > > I tested it on various IMX6 (S and Q) boards and the default SDMA firmware > that is included in ROM does work properly. The SDMA interrupt counter does > not stop increment (which means the SDMA does not stop working or the ACK > is working) and I see a lot of 0x00 (sometimes other bytes) which are added > to the tty buffer which are not part of the data transfer. > Jiada claimed that there is a firmware which makes it work but failed to > provide me a link to the firmware. All he said was that it can not be > shipped as part of the kernel due to license issues. I've found a firmware > blob in the FSL-tree but this firmware causes only TTY-overflows an *no* > data is transmitted. > > Currently I see no other way out. > > Fixes: 068500e08dc8 ("serial: imx: initialized DMA w/o HW flow enabled") > Cc: Fabio Estevam <fabio.estevam@freescale.com> > Cc: Jiada Wang <jiada_wang@mentor.com> > Cc: nicolae.rosia@gmail.com > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Thanks, this fixes Bluetooth operation on a imx6sl-warp running without SDMA firmware.
Two suggestions:
1. You should Cc stable as it affects 4.0 also
2. It doesn't apply cleanly against linux-next, so I think Greg will have problems applying it.
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