SDHC very slow (300-600 KB/s) on i.MX25 board

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SDHC very slow (300-600 KB/s) on i.MX25 board

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stkoch
Contributor I

Hi,

I have ported linux-3.7-rc4 to a board with i.MX257 CPU.

As distribution I use Debian squeeze.

Booting time (with Xorg and IceWM) is different with different SD-Cards.

Boot time with 2GB Standard micro SD-Card: over 2:30 minutes

Boot time with 4GB Class 10 micro SDHC: 1:40 minutes

Boot time with 8GB UHS-1 micro SDHC: 1:15 minutes

Boot time with NFS (Network without SD/SDHC): 40 seconds

Starting applications is faster with NFS as with SD/SDHC.

At SD/SDHC linux is system is waiting a lot of time.

Then CPU can not run at 100% usage, so system is not so fast as possible.

Tests with dd give ratings from a. e. 300 KB/s (this could be a Class 10 card).

But there is a relationship with slower and faster SD/SDHC-cards:

A UHS card works faster than a class 10 card an so on.

And a Standard 2GB SD card is the slowest.

But the Standard 2GB SC card works with a card reader connected to an Notebook faster than the UHS-1 Card in the imx257 Target system with imx integrated SDHC controller.

How to solve this problem?

Is it a driver issue?

Thanks

Stefan Koch


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9 Replies

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SecondTechCo
Contributor IV

Has anyone ever solved this problem with the slowness ?

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YixingKong
Senior Contributor IV

Stefan

This discussion is closed since no activity. If you still need help, please feel free to reply with an update to this discussion, or create another discussion.

Thanks,

Yixing

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madhurabhashini
Contributor II

Hi,

I too have a similar problem with iMX 25. When I boot from NAND and stop at autoboot, I insert my Sandisk SDHC 8 GB card and run "mmcinfo" on the command line. It takes about more than 5 min , but there is no info displayed. However , "mmclist" gives me FSL_ESDHC: 0. I use L2.6.31 kernel and uboot 2009.08. Kindly help.

Thanks,

Madhu

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YixingKong
Senior Contributor IV

Stefan

We have not got your response yet and will close the diacussion in 3 days. If you still need help, please feel free to

reply with an update to this discussion.
Thanks,
Yixing

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YixingKong
Senior Contributor IV


Stefan

We are sorry for getting back to you so late. Are you still stuck with the issue? If you have somehow to resolved the issue, can we close the discussion? If you still need Freescale help, please feel free to contact us.

Thanks,

Yixing

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CLI
Contributor I

I am looking at this issue too. With Linux 3.8.8 and iMX253, the sd card write speed is less than 100KB/s, although the sd card clock is 33M.

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fabio_estevam
NXP Employee
NXP Employee

Hi Hongliang,

Could you please try a more recent kernel, such as 3.14-rc4?

If the problem is still present, please report it to linux-mmc mailing list.

Regards,

Fabio Estevam

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maximkochetkov
Contributor II

I have the same problem even with kernel 4.9.5. Kernel 2.6.35 from Freescale LTIB works great.

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TrondAre
Contributor I

Hi Stefan,

We have similar results with the 3.7/3.8 drivers & the MX25. Did you get any feedback from anyone on this?

/TrondAre

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