On Tue, Dec 03, 2019 at 09:05:23AM +0000, Jisheng Zhang wrote: > > > > > > eg. drivers/mmc/host/sdhci-of-dwcmshc.c > > > > > Thanks for the suggestion! Christoph's suggestion can prevent the the issue > > from the block layer, thus the code can be shared across all > > To be honest, I did consider similar solution from block layer, I.E set > the seg_boundary_mask, when submitting the workaround last year, but per > my understanding, SDHCI limitation is the physical DMA addr can't span one > specific boundary, As in exactly one boundary and not an alignment? Where the one boundary is not a power of two and thus can't be expressed? > so setting seg_boundary_mask w/ blk_queue_segment_boundary > can't work. I'm not sure I understand blk_queue_segment_boundary() properly. > May Christoph help to clarify? > > From another side, drivers/ata/libata-sff.c also workaround the 64K phy DMA > boundary limitation itself rather than from block layer. As far as I can tell that workaround should use the segment boundary setting as well.
