* Andreas Kemnade <andreas@xxxxxxxxxxxx> [230113 23:12]: > From: "H. Nikolaus Schaller" <hns@xxxxxxxxxxxxx> > > OMAP processors support 32 channels but there is no check or > inspect this except booting a device and looking at dmesg reports > of not available channels. > > Recently some more subsystems with DMA (aes1+2) were added filling > the list of dma channels beyond the limit of 32 (even if other > parameters indicate 96 or 128 channels). This leads to random > subsystem failures i(e.g. mcbsp for audio) after boot or boot > messages that DMA can not be initialized. > > Another symptom is that > > /sys/kernel/debug/dmaengine/summary > > has 32 entries and does not show all required channels. > > Fix by disabling unused (on the GTA04 hardware) mcspi1...4. > Each SPI channel allocates 4 DMA channels rapidly filling > the available ones. > > Disabling unused SPI modules on the OMAP3 SoC may also save > some energy (has not been checked). Applying this into omap-for-v6.4/dt based on what we discussed in this thread earlier. Thanks, Tony
