Hi Fabio, Am 12.09.19 um 20:23 schrieb Fabio Estevam: > Hi Philipp, > > Thanks for submitting these fixes. > > On Wed, Sep 11, 2019 at 11:50 AM Philipp Puschmann > <philipp.puschmann@xxxxxxxxx> wrote: >> >> For some years and since many kernel versions there are reports that >> RX UART DMA channel stops working at one point. So far the usual workaround was >> to disable RX DMA. This patches try to fix the underlying problem. >> >> When a running sdma script does not find any usable destination buffer to put >> its data into it just leads to stopping the channel being scheduled again. As >> solution we we manually retrigger the sdma script for this channel and by this >> dissolve the freeze. >> >> While this seems to work fine so far a further patch in this series increases >> the number of RX DMA periods for UART to reduce use cases running into such >> a situation. >> >> This patch series was tested with the current kernel and backported to >> kernel 4.15 with a special use case using a WL1837MOD via UART and provoking >> the hanging of UART RX DMA within seconds after starting a test application. >> It resulted in well known >> "Bluetooth: hci0: command 0x0408 tx timeout" >> errors and complete stop of UART data reception. Our Bluetooth traffic consists >> of many independent small packets, mostly only a few bytes, causing high usage >> of periods. >> >> >> Philipp Puschmann (4): >> dmaengine: imx-sdma: fix buffer ownership >> dmaengine: imx-sdma: fix dma freezes >> serial: imx: adapt rx buffer and dma periods >> dmaengine: imx-sdma: drop redundant variable > > I have some suggestions: > > 1. Please split this in two series: one for dmaengine and other one for serial > > 2. Please add Fixes tag when appropriate, so that the fixes can be > backported to stable kernels. > > 3. Please Cc Robin and Andy > > Thanks > Thanks for the hints. I will apply them if the contentual feedback is positive. p.s. Did you forget to add Andy? I don't see a Andy in the to- and cc-list.
