On Wed, 2022-08-03 at 09:23 -0700, Bart Van Assche wrote: > On 8/2/22 16:40, yohan.joung@xxxxxx wrote: > > Is it possible by adding only max_sector to increase the data > > buffer size? > > Yes. > > > I think the data buffer will split to 512 KiB, because the sg_table > > size is SG_ALL > > I don't think so. With this patch applied, the limits supported by > the > UFS driver are as follows: > > .sg_tablesize = SG_ALL, /* 128 */ > .max_segment_size = PRDT_DATA_BYTE_COUNT_MAX, /* 256 > KiB*/ > .max_sectors = (1 << 20) / SECTOR_SIZE, /* 1 MiB > */ > > So the maximum data buffer size is min(max_sectors * 512, > sg_tablesize * > max_segment_size) = min(1 MiB, 128 * 256 KiB) = 1 MiB. On a system > with > 4 KiB pages, the data buffer size will be 128 * 4 KiB = 512 MiB if > none > of the pages involved in the I/O are contiguous. > > Bart. Bart, This change just increases the shost->max_sectors limit from 501KB to 1Mb, but the final value will be overridden by the optimal transfer length defined in the VPD, right? Kind regards, Bean
