On 2018-03-29 16:20, Nicolas Ferre wrote: > On 29/03/2018 at 15:10, Peter Rosin wrote: >> On a sama5d31 with a Full-HD dual LVDS panel (132MHz pixel clock) NAND >> flash accesses have a tendency to cause display disturbances. Add a >> module param to disable DMA from the NAND controller, since that fixes >> the display problem for me. >> >> Signed-off-by: Peter Rosin <[email protected]> >> --- >> drivers/mtd/nand/raw/atmel/nand-controller.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c >> b/drivers/mtd/nand/raw/atmel/nand-controller.c >> index b2f00b398490..2ff7a77c7b8e 100644 >> --- a/drivers/mtd/nand/raw/atmel/nand-controller.c >> +++ b/drivers/mtd/nand/raw/atmel/nand-controller.c >> @@ -129,6 +129,11 @@ >> #define DEFAULT_TIMEOUT_MS 1000 >> #define MIN_DMA_LEN 128 >> >> +static bool atmel_nand_avoid_dma __read_mostly; >> + >> +MODULE_PARM_DESC(avoiddma, "Avoid using DMA"); >> +module_param_named(avoiddma, atmel_nand_avoid_dma, bool, 0400); > > We had the DT parameter "atmel,nand-has-dma" for this purpose and it was > associated with a module parameter as well (use_dma,). > > Is it only managed by old DT binding?
Saw it, but I need the reverse. I.e. *not* using DMA. And I didn't think this belonged in DT since in some sense it doesn't really describe HW so I went with a module parameter. Cheers, Peter
