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 -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel