On 12/18/2015 6:33 PM, Måns Rullgård wrote: > Julian Margetson writes: > >> On 12/18/2015 1:18 PM, Måns Rullgård wrote: >>> Julian Margetson writes: >>> >>>> On 12/18/2015 8:49 AM, Måns Rullgård wrote: >>>>> Andy Shevchenko writes: >>>>> >>>>>>>> [ 5.206125] Unable to handle kernel paging request for data at >>>>>>>> address 0x00000000 >>>>>>>> [ 5.228546] Faulting instruction address: 0xc043a2c8 >>>>>>>> [ 5.248577] Vector: 300 (Data Access) at [eddafae0] >>>>>>>> [ 5.268658] pc: c043a2c8: sata_dwc_qc_issue+0xb8/0x204 >>>>>>> Well, that's not good. Can you translate that address to a line of >>>>>>> code? >>>>>> Besides that, can you enable DYNAMIC_DEBUG in the config and append >>>>>> 'dw_dmac_core.dyndbg dw_dmac.dyndbg' to the kernel cmdline? >>>>> Enabling debug messages in the sata_dwc driver might also be informative. >>>>> >>>> Changed the sata-dwc to a module . >>>> >>>> [ 18.475140] sata-dwc 4bffd1000.sata: sata_dwc_qc_prep_by_tag: dma_dwc_xfer_setup returns NULL >>>> [ 18.535698] sata-dwc 4bffd1000.sata: sata_dwc_qc_prep_by_tag: dma_dwc_xfer_setup returns NULL >>> That's strange. The only way that can happen is if >>> dmaengine_prep_slave_sg() return NULL, and that really shouldn't be >>> happening. Did you turn on debug messages in dw_dma? You can enable >>> some extra debug messages by adding "#define VERBOSE_DEBUG" at the top >>> of drivers/dma/dw/core.c >>> >> [ 17.526173] sata-dwc 4bffd1000.sata: sata_dwc_qc_prep_by_tag: dma_dwc_xfer_setup returns NULL >> [ 17.600124] sata-dwc 4bffd1000.sata: sata_dwc_qc_prep_by_tag: dma_dwc_xfer_setup returns NULL >> [ 17.662978] sata-dwc 4bffd1000.sata: sata_dwc_qc_prep_by_tag: dma_dwc_xfer_setup returns NULL > Could you post the entire kernel log? There might be important > information before the errors start. >