Hi Geert, On Fri, Jun 28, 2019 at 02:10:01PM +0200, Geert Uytterhoeven wrote: > On Wed, Jun 26, 2019 at 8:15 PM Eugeniu Rosca <roscaeugeniu@xxxxxxxxx> wrote: [..] > I'm not such a big fan of WARN()... [..] > > rcar-dmac e7300000.dma-controller: rcar_dmac_prep_slave_sg: bad parameter: len=1, id=19 > > Which would be followed by > > sh-sci e6e88000.serial: Failed preparing Tx DMA descriptor > > pointing to the sh-sci driver, right? > > The id=19 points to channel 0x13, i.e. SCIF2, according to > arch/arm64/boot/dts/renesas/r8a7795.dtsi. Thank you for the detailed rationale. Much appreciated. FTR, the patch landed in vkoul/slave-dma.git, as commit https://git.kernel.org/pub/scm/linux/kernel/git/vkoul/slave-dma.git/commit/?h=next&id=78efb76ab4dfb8f ("dmaengine: rcar-dmac: Reject zero-length slave DMA requests") -- Best Regards, Eugeniu.