On Tue, Apr 11, 2017 at 2:28 AM, Bough Chen <haibo.chen@xxxxxxx> wrote: >> -----Original Message----- <snip> >> >> I've moved on to 4.11-rc5 and notice that I'm always seeing that on a failure the >> imx sdhc not able to determine a min/max tuning delay: >> >> 4.11.0-rc5: >> [ 48.812381] mmc0: card aaaa removed >> [ 49.793392] mmc0: host does not support reading read-only switch, >> assuming write-enable >> [ 49.810294] sdhci_execute_tuning >> [ 49.813612] esdhc_executing_tuning >> [ 49.968154] sdhci-esdhc-imx 2198000.usdhc: tuning failed at 0x7f >> ret -5 (min=127/max=128) >> ^^^^ added debug shows -EIO returned from mmc_send_tuning although I've >> also seen -84 get returned >> [ 49.980540] mmc0: tuning execution failed: -5 >> [ 49.984974] mmc0: ddr50 tuning failed >> [ 49.989068] mmc0: new ultra high speed DDR50 SDHC card at address aaaa >> [ 49.999844] mmcblk0: mmc0:aaaa SL08G 7.40 GiB >> >> I've also found that if I revert '9faac7b mmc: sdhci: enable tuning for DDR50' >> thus skipping the tuning the issue goes away however note that occasionally I >> do see a transfer error that perhaps is retried [ 361.067763] mmc0: card aaaa >> removed [ 361.412732] mmc0: host does not support reading read-only switch, >> assuming write-enable [ 361.429719] mmc0: new ultra high speed DDR50 SDHC >> card at address aaaa [ 361.443060] mmcblk0: mmc0:aaaa SL08G 7.40 GiB >> [ 361.465658] mmcblk0: p1 [ 362.422335] mmc0: card aaaa removed >> [ 362.752719] mmc0: host does not support reading read-only switch, assuming >> write-enable [ 362.769675] mmc0: new ultra high speed DDR50 SDHC card at >> address aaaa [ 362.782900] mmcblk0: mmc0:aaaa SL08G 7.40 GiB [ 362.805996] >> mmcblk0: error -84 transferring data, sector 0, nr 8, cmd response 0x900, card >> status 0xb00 ^^^^ occasionally see this error but because retries occur at the >> block level it still works [ 362.931689] mmcblk0: p1 >> >> Again with 9faac7b reverted and some extra debugging: >> [ 33.823170] mmc0: host does not support reading read-only switch, >> assuming write-enable >> [ 33.847185] mmc0: new ultra high speed DDR50 SDHC card at address aaaa >> [ 33.856063] mmcblk0: mmc0:aaaa SL08G 7.40 GiB >> [ 33.874227] mmcblk0: error -84 transferring data, sector 0, nr 8, >> cmd response 0x900, card status 0xb00 >> [ 33.896829] mmcblk0: error -84 transferring data, sector 0, nr 8, >> cmd response 0x900, card status 0xb00 >> [ 33.906312] mmcblk0: error -84 transferring data, sector 0, nr 8, >> cmd response 0x900, card status 0xb00 >> [ 34.022117] mmcblk0: error 0 transferring data, sector 0, nr 8, cmd >> response 0x900, card status 0xb00 >> ^^^^ added debugging shows retries at block level and eventually all is fine >> [ 34.031500] mmcblk0: p1 >> >> So far every DDR50 card I have (several Kingston and Sandisk card >> models) behaves like this. >> >> I tried adding a settling delay when VSELECT was changed in the sdhci-esdhc- >> imx driver and that didn't help. >> > Hi Tim > > Which imx6 soc do you use? From your log, I notice you use the MAN tuning method, so I guess you use imx6qdl. > > imx usdhc has an IC bug. For the tuning procedure, the first pass tuning delay value must bigger than 10. > Due to DDR50 timing is not that rigorous, so maybe even when we just add 1 delay cell, tuning can pass, but this trigger the internal IC bug, then you meet the following issue just as you meet: > sdhci-esdhc-imx 2198000.usdhc: tuning failed at 0x7f ( min=127/max=128) > Haibo, Thanks for the response. Yes, this issue is seen on the IMX6DQ and IMX6SDL. Can you point me to information on this bug? I don't see it in the latest IMX6DQCE.pdf errata document. > So you can change the ESDHC_TUNE_CTRL_MIN from 0 to 15, then you can see the DDR50 tuning return to normal. > > For the STD tuning method, you can add the property 'fsl,tuning-start-tap = <20>' in dts. > > All this make the first trying tuning delay value larger than 10, to avoid the internal IMX USDHC IC bug. > > SDR104 card do not has this issue, because for SDR104 card, the first pass tuning value normally larger than 10. > unfortunately, this does not resolve the issue. I tried ESDHC_TUNE_CTRL_MIN of 15, 20, and 30 and they all produce the same issue around 20% of insertions: sdhci-esdhc-imx 2198000.usdhc: tunning failed at 0x7f ret -84 Here are some min/max tuning values from some various cards I have: - Samsung SL08G DDR50: min=8 max=37 - Kingston SD8GB DDR50: min=8 max=36 - Sandisk SS16G DDR50: min=10 max=37 - Sandisk SU08G DDR50: min=9 max=36 - Samsung Pro 00000 SDR104: min=14 max=26 - Kingston SDR104 SDCIT: min=25 max=36 All of the DDR50 cards above fail in the same way appx 20% of insertions. Has anyone else been able to confirm they see the same issue on IMX6 boards with UHS-I support and DDR50? Regards, Tim -- 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
