On Wed, Sep 3, 2014 at 11:11 PM, Jean-Michel Hautbois
<jhautbois@xxxxxxxxx> wrote:
> 2014-09-03 10:15 GMT+02:00 Dong Aisheng <dongas86@xxxxxxxxx>:
>> Hi JM,
>>
>> On Tue, Sep 2, 2014 at 11:10 PM, Jean-Michel Hautbois
>> <jhautbois@xxxxxxxxx> wrote:
>>> 2014-09-02 11:20 GMT+02:00 Jean-Michel Hautbois
>>> <jean-michel.hautbois@xxxxxxxxxxx>:
>>>> Hi there,
>>>>
>>>> I start a new thread, as I have done lots of test and this will be clearer.
>>>> I have problems reading and writing eMMC on my i.MX6 board with 3.17-rc3.
>>>> Sometimes I don't have read errors explicitly in dmesg, but fdisk has
>>>> no effects.
>>>> I activated MMC debug in my config file, and here is an extract of
>>>> mmc0 register dump and all mmc1 part.
>>>> On Freescale kernel, I confirm it works well with the same board and
>>>> sample, I can write a partition on mmc1.
>>>
>>
>> My iMX6Q SabreSD board seems ok.
>> What board did you use?
>> What reading/writing problems did you meet?
>> I did not see errors in your log.
>> Can you paste the error log?
>
> When CONFIG_MMC_DEBUG=y there is no error.
> When CONFIG_MMC_DEBUG=n then, I get :
>
> [ 2.036958] SW2: Restricting voltage, 3300000-1950000uV
> [ 2.036965] mmc1: Switching to 1.8V signalling voltage failed
> [ 2.043714] mmc1: new DDR MMC card at address 0001
> [ 2.044738] mmcblk1: mmc1:0001 SEM02G 1.82 GiB
> [ 2.045007] mmcblk1rpmb: mmc1:0001 SEM02G partition 3 128 KiB
> [ 2.048345] mmcblk1: error -84 transferring data, sector 0, nr 8,
> cmd response 0x900, card status 0xb00
It seems you're using Sandisk eMMC chip, right?
We ever got an errata of Sandisk eMMC that it needs certain delay
befor sending cmd13
after cmd6.
We tried 1ms seems ok for such eMMC chip.
You may give a try.
e.g.
diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 49f04bc..83d17a9 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -440,6 +440,12 @@ int __mmc_switch(struct mmc_card *card, u8 set,
u8 index, u8 value,
if (!use_busy_signal)
return 0;
+ /*
+ * WORKAROUND: for Sandisk eMMC cards, it might need certain delay
+ * before sending CMD13 after CMD6
+ */
+ mdelay(1);
+
/* Must check status to be sure of no errors */
timeout = jiffies + msecs_to_jiffies(MMC_OPS_TIMEOUT_MS);
do {
BTW, you should also make sure the signal quality is not bad which may
also cause such issue.
Regards
Dong Aisheng
> [ 2.048352] mmcblk1: retrying using single block read
> [ 2.048858] mmcblk1: error -84 transferring data, sector 0, nr 8,
> cmd response 0x900, card status 0x0
> [ 2.048933] end_request: I/O error, dev mmcblk1, sector 0
> [ 2.049449] mmcblk1: error -84 transferring data, sector 1, nr 7,
> cmd response 0x900, card status 0x0
> [ 2.049459] end_request: I/O error, dev mmcblk1, sector 1
> [ 2.049969] mmcblk1: error -84 transferring data, sector 2, nr 6,
> cmd response 0x900, card status 0x0
> [ 2.049978] end_request: I/O error, dev mmcblk1, sector 2
> [ 2.050484] mmcblk1: error -84 transferring data, sector 3, nr 5,
> cmd response 0x900, card status 0x0
> [ 2.050493] end_request: I/O error, dev mmcblk1, sector 3
> [ 2.050998] mmcblk1: error -84 transferring data, sector 4, nr 4,
> cmd response 0x900, card status 0x0
> [ 2.051008] end_request: I/O error, dev mmcblk1, sector 4
> [ 2.051512] mmcblk1: error -84 transferring data, sector 5, nr 3,
> cmd response 0x900, card status 0x0
> [ 2.051521] end_request: I/O error, dev mmcblk1, sector 5
> [ 2.052028] mmcblk1: error -84 transferring data, sector 6, nr 2,
> cmd response 0x900, card status 0x0
> [ 2.052038] end_request: I/O error, dev mmcblk1, sector 6
> [ 2.052542] mmcblk1: error -84 transferring data, sector 7, nr 1,
> cmd response 0x900, card status 0x0
> [ 2.052551] end_request: I/O error, dev mmcblk1, sector 7
> [ 2.052620] Buffer I/O error on device mmcblk1, logical block 0
> [ 2.053338] mmcblk1: error -84 transferring data, sector 0, nr 8,
> cmd response 0x900, card status 0xb00
> [ 2.053345] mmcblk1: retrying using single block read
> [ 2.053849] mmcblk1: error -84 transferring data, sector 0, nr 8,
> cmd response 0x900, card status 0x0
> [ 2.053859] end_request: I/O error, dev mmcblk1, sector 0
> [ 2.054378] mmcblk1: error -84 transferring data, sector 1, nr 7,
> cmd response 0x900, card status 0x0
> [ 2.054388] end_request: I/O error, dev mmcblk1, sector 1
> [ 2.054892] mmcblk1: error -84 transferring data, sector 2, nr 6,
> cmd response 0x900, card status 0x0
> [ 2.055403] mmcblk1: error -84 transferring data, sector 3, nr 5,
> cmd response 0x900, card status 0x0
> [ 2.055917] mmcblk1: error -84 transferring data, sector 4, nr 4,
> cmd response 0x900, card status 0x0
> [ 2.056428] mmcblk1: error -84 transferring data, sector 5, nr 3,
> cmd response 0x900, card status 0x0
> [ 2.056937] mmcblk1: error -84 transferring data, sector 6, nr 2,
> cmd response 0x900, card status 0x0
> [ 2.057446] mmcblk1: error -84 transferring data, sector 7, nr 1,
> cmd response 0x900, card status 0x0
> [ 2.057460] Buffer I/O error on device mmcblk1, logical block 0
> [ 2.057506] mmcblk1: unable to read partition table
>
> So, I can't get MMC_DEBUG info when the problem occurs, as it disappears :/.
> Thanks,
> JM
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