On Wed, Nov 16, 2016 at 11:51 AM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > To improve this behaviour and shorten the card initialization time, we need to > allow using CMD13 as polling method to find out when the card stops signaling > busy. Although, enabling CMD13 polling may also introduce other issues as > according to the JEDEC spec, it's not the recommended method. Especially it > mentions that CRC errors may be triggered when sending a CMD13 command during a > bus timing change. > > To deal with these issues, we need to change from ignoring those CRC errors but > instead continue to treat the card as being busy and continue to poll with > CMD13. Perhaps this behaviour is one of reasons to why the earlier CMD13 polling > method didn't work out well. > > This series requires extensive testing, please help with that! I cloned the MMC tree "next" and applied the patches on top. (I guess if you want wider testing it's good to publish a branch, but I'd recommend just putting it into linux-next, it seems solid to me.) Tested on my previously problematic APQ8060 Dragonboard, it switches to highspeed and works like a charm! Now the eMMC comes up smacky right after registering the host: [ 1.955105] mmci-pl18x 12400000.sdcc: mmc0: PL180 manf 51 rev0 at 0x12400000 irq 197,0 (pio) [ 1.955149] mmci-pl18x 12400000.sdcc: DMA channels RX none, TX none [ 1.964202] mmci-pl18x 12400000.sdcc: Voltage switch failed [ 2.031744] mmci-pl18x 12180000.sdcc: Got CD GPIO [ 2.031829] mmci-pl18x 12180000.sdcc: Got WP GPIO [ 2.040263] mmci-pl18x 12180000.sdcc: DMA channels RX none, TX none [ 2.094161] mmc0: new high speed MMC card at address 0001 [ 2.095590] mmcblk0: mmc0:0001 SEM04G 3.69 GiB [ 2.120905] mmcblk0boot0: mmc0:0001 SEM04G partition 1 1.00 MiB [ 2.133068] mmcblk0boot1: mmc0:0001 SEM04G partition 2 1.00 MiB [ 2.139657] mmcblk0rpmb: mmc0:0001 SEM04G partition 3 128 KiB [ 2.158004] mmcblk0: p1 p2 p3 p4 < p5 p6 p7 p8 p9 p10 p11 p12 p13 p14 p15 p16 p17 p18 p19 p20 p21 > Tested-by: Linus Walleij <linus.walleij@xxxxxxxxxx> Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
