> -----Original Message----- > From: linux-omap-owner@xxxxxxxxxxxxxxx > [mailto:linux-omap-owner@xxxxxxxxxxxxxxx] On Behalf Of Peter Ujfalusi > Sent: Monday, October 04, 2010 1:48 PM > To: Tony Lindgren > Cc: linux-omap@xxxxxxxxxxxxxxx; Jarkko Nikula; > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Subject: [PATCH v4 1/4] omap: dma: Fix buffering disable bit > setting for omap24xx > > From: ext Jarkko Nikula <jhnikula@xxxxxxxxx> > > An errata workaround for omap24xx is not setting the > buffering disable bit > 25 what is the purpose but channel enable bit 7 instead. ... > diff --git a/arch/arm/plat-omap/dma.c > b/arch/arm/plat-omap/dma.c index ec7eddf..6914ccf 100644 > --- a/arch/arm/plat-omap/dma.c > +++ b/arch/arm/plat-omap/dma.c > @@ -999,8 +999,9 @@ void omap_start_dma(int lch) > * Errata: On ES2.0 BUFFERING disable must be set. > * This will always fail on ES1.0 > */ Sorry, I didn't catch this with earlier patch. Looks like wrong comment. only on 2430ES1.0 and for all omap2420, buffer disable should be set. I feel below description will be useful to the reader: "Errata: Inter Frame DMA buffering issue(All OMAP2420 and OMAP2430ES1.0): DMA will wrongly buffer elements if packing and bursting is enabled. This might result in data gets stalled in FIFO at the end of the block. Workaround: DMA channels must have BUFFERING_DISABLED bit set to guarantee no data will stay in the DMA FIFO in case inter frame buffering occurs. -Manjunath-- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
