Thread (12 messages) 12 messages, 5 authors, 2019-12-10

Re: [PATCH v5 0/3] Fix UART DMA freezes for i.MX SOCs

From: Jan Lübbe <jlu@pengutronix.de>
Date: 2019-09-23 15:09:42
Also in: dmaengine, lkml

On Mon, 2019-09-23 at 17:06 +0200, Philipp Puschmann wrote:
Thanks for testing.
With my local setup i still have very few tx timeouts too. But i think they have a different
cause and especially different consequences. When the problem addressed by this series
appear you get a whole bunch of tx timeouts (and maybe errors from Bluetooth
layer) and monitoring received Bluetooth packets with hciconfig shows a
complete freeze of rx counter. Only resetting the hci_uart driver and the wl1837mon then helps.
With these patches applied the rx data shold still coming in even if a single or
multiple tx timeout error happen. I'm not sure where the error comes from and what the
consequences for the Bluetooth layer are.
For testing, I've used a UART connected to my development host and
configured *mismatching* baud rates. Sending /dev/urandom from the host
to the i.MX6 then triggered the DMA hang (because each character
triggers and error indication, which "uses" a full buffer).

Regards,
Jan
-- 
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