On 07/27/2018 05:55 AM, Robin Murphy wrote: > Hi Grygorii, > > Thanks for the report. > > On 27/07/18 00:45, Grygorii Strashko wrote: > [...] >> With this series applied I can't boot TI ARM32 am574x-idk any more. >> >> And log output is full of "DMA mask not set" - > > That's somewhat expected - as the relevant commit message mentions, > there will be bugs flushed out by this change, but the point is to fix > them :) > >> nobody sets dma_mask for platform bus in case of OF boot :( > > Right, after a brief investigation, that one turns out to be nice and > straightforward to explain and fix; I'll write up the patch shortly. > > [...] >> [ 3.793493] ti-qspi 4b300000.qspi: dma_alloc_coherent failed, using >> PIO mode >> [ 3.801088] Unable to handle kernel NULL pointer dereference at >> virtual address 00000080 > [...] >> [ 4.602777] [<c04d87a4>] (omap_dma_write) from [<c04d8dc0>] >> (omap_dma_start_desc+0x78/0x150) >> [ 4.611258] [<c04d8d48>] (omap_dma_start_desc) from [<c04d9028>] >> (omap_dma_issue_pending+0x90/0x98) >> [ 4.620347] r9:ed002780 r8:00000000 r7:00000010 r6:ee2bdd00 >> r5:ee2bdd4c r4:ee2bdd00 >> [ 4.628130] [<c04d8f98>] (omap_dma_issue_pending) from [<c0608d1c>] >> (ti_qspi_dma_xfer+0x8c/0x13c) >> [ 4.637039] r5:00000000 r4:ee7e1b28 >> [ 4.640636] [<c0608c90>] (ti_qspi_dma_xfer) from [<c06090b0>] >> (ti_qspi_exec_mem_op+0x2e4/0x32c) > > Hooray, a real bug! Since dma_alloc_coherent() could have failed due to > lack of memory or any other reason, that's not even directly related to > this change, we've simply helped uncover it. I guess that PIO fallback > path hasn't been tested recently, because it clearly doesn't work. It > would be good if someone who knows the ti-qspi driver and has the means > to test it could figure that one out before also adding the missing > dma_set_coherent_mask() call. yes. ti-qspi has an issues with PIO mode. But, reason of failure is this warning: [ 3.482502] WARNING: CPU: 0 PID: 1 at ./include/linux/dma-mapping.h:516 ti_qspi_probe+0x4a4/0x50c which is caused by this series - which makes coherent_dma_mask constantly 0 by default, so dma_alloc_coherent() - fails. > Robin. -- regards, -grygorii -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
