FYI: Source files of the Dawicontrol DC 2976 UW SCSI board (PCI): https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/scsi/sym53c8xx_2?h=v5.4-rc7 /* * DMA addressing mode. * * 0 : 32 bit addressing for all chips. * 1 : 40 bit addressing when supported by chip. * 2 : 64 bit addressing when supported by chip, * limited to 16 segments of 4 GB -> 64 GB max. */ #define SYM_CONF_DMA_ADDRESSING_MODE CONFIG_SCSI_SYM53C8XX_DMA_ADDRESSING_MODE Cyrus config: CONFIG_SCSI_SYM53C8XX_DMA_ADDRESSING_MODE=1 I will configure “0 : 32 bit addressing for all chips” for the RC8. Maybe this is the solution. > On 13. Nov 2019, at 12:02, Christoph Hellwig <hch@xxxxxx> wrote: > > Interesting. Give me some time to come up with a real fix, as drivers > really should not mess with GFP flags for these allocations, and even > if they did swiotlb is supposed to take care of any resulting problems.