On 12/18/2015 10:34 PM, Andy Shevchenko wrote: > On Sat, Dec 19, 2015 at 1:16 AM, Måns Rullgård wrote: >> Julian Margetson writes: >> >>> 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. >>>> >>> >>> =~=~=~=~=~=~=~=~=~=~=~= PuTTY log 2015.12.18 15:01:48 =~=~=~=~=~=~=~=~=~=~=~= >>> [ 0.000000] Using Canyonlands machine description >>> [ 0.000000] Initializing cgroup subsys cpu >>> [ 0.000000] Linux version 4.4.0-rc5-Sam460ex (root@julian-VirtualBox) (gcc version 4.8.2 (Ubuntu 4.8.2-16ubuntu3) ) #8 PREEMPT Fri Dec 18 13:36:34 AST 2015 >>> [ 0.000000] Zone ranges: >>> [ 0.000000] DMA [mem 0x0000000000000000-0x000000002fffffff] >>> [ 0.000000] Normal empty >>> [ 0.000000] HighMem [mem 0x0000000030000000-0x000000007fffffff] >>> [ 0.000000] Movable zone start for each node >>> [ 0.000000] Early memory node ranges >>> [ 0.000000] node 0: [mem 0x0000000000000000-0x000000007fffffff] >>> [ 0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x000000007fffffff] >>> [ 0.000000] MMU: Allocated 1088 bytes of context maps for 255 contexts >>> [ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 522752 >>> [ 0.000000] Kernel command line: root=/dev/sda8 console=ttyS0,115200 console=tty0 dw_dmac_core.dyndbg dw_dmac.dyndbg > I would suggest to use console=tty1 instead of console=tty0. > >> [...] >> >>> [ 13.643415] systemd[1]: Mounted Configuration File System. >>> [ 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 >> This log is weird. The sata_dwc_probe() function prints several things >> (one using dev_notice()), for instance this: >> >> /* Read the ID and Version Registers */ >> idr = in_le32(&hsdev->sata_dwc_regs->idr); >> versionr = in_le32(&hsdev->sata_dwc_regs->versionr); >> dev_notice(&ofdev->dev, "id %d, controller version %c.%c%c\n", >> idr, ver[0], ver[1], ver[2]); >> >> The dw_dma_probe() function also prints a line: >> >> dev_info(chip->dev, "DesignWare DMA Controller, %d channels\n", >> pdata->nr_channels); >> >> These messages are nowhere to be seen in your log, nor are numerous >> others that really must appear before before sata_dwc_qc_prep_by_tag() >> can be called. >> > It would be better to add 'ignore_loglevel' to the cmdline as well. > >> I'd like to note that the driver works on my Sigma Designs based system >> using a different DMA controller, so it's not completely broken. The >> DMA driver could still be faulty, but that still doesn't explain the >> missing kernel messages. >> >> -- >> Måns Rullgård >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> Please read the FAQ at http://www.tux.org/lkml/ > >