I think it is more of a timing issue than mechanical per se - I'm
running an own-build kernel (2.6.28-rc4) on top of intrepid on an acer
aspire one, and was experiencing 'mmcblk0: error -110 transferring data'
errors on a 16Gb SDHC card in the left hand slot.
The card was enabled for UDMA66 and hdparm -t /dev/mmcblk0 was reporting
transfer rates in excess of 20Mb/sec, but it was unreliable.
I had a look at the kernel source, specifically file drivers/mmc/host
/sdhci-pci.c, within function jmicron_probe: First thing it does is set
up the quirks mode:
if (chip->pdev->revision == 0) {
chip->quirks |= SDHCI_QUIRK_32BIT_DMA_ADDR |
SDHCI_QUIRK_32BIT_DMA_SIZE |
SDHCI_QUIRK_32BIT_ADMA_SIZE |
SDHCI_QUIRK_RESET_AFTER_REQUEST |
SDHCI_QUIRK_BROKEN_SMALL_PIO |
SDHCI_QUIRK_FORCE_HIGHSPEED;
}
I've commented out the SDHCI_QUIRK_FORCE_HIGHSPEED and rebuild the
kernel ... no more errors at all, but of course throughput is now only
about 11Mb/sec. Much better to be stable than fast, IMHO.
Obviously this will only work for jmicron controllers ... I think that
the bug is elsewhere, and all this does is mask the root cause of the
problem (IIRC someone on the acer aspire one forum thought it was a
timing / buffering / interrupt issue, but can't quote exactly).
R.
--
SDHC Card reader I/O errors on Hardy
https://bugs.launchpad.net/bugs/247819
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