and Braswell eMMC and SDXC controllers share the same IDs. Like in
the PCI case, Braswell eMMC needs the SDHCI_QUIRK_DATA_TIMEOUT_1MHZ
quirk (see r311794 for the corresponding change to the sdhci(4) PCI
PCI front-end), though. However, due to the shared ACPI IDs, this
is trickier to do.
- Intel Apollo Lake eMMC and SDXC controllers are affected by the
APL18 ("Using 32-bit Addressing Mode With SD/eMMC Controller May
Lead to Unpredictable System Behavior") silicon bug [1]. When this
erratum hits, typically both SDHCI and XHCI controllers wedge.
According to Intel, using ADMA2 with 64-bit addressing and 96-bit
descriptors serves as a workaround. Until such times when sdhci(4)
has ADMA2 support, flag DMA as broken for affected interfaces.
This turns out to work around the problem, too, at the cost of
performance.
- In the sdhci(4) ACPI front-end, probe the Intel Apollo Lake eMMC
and SDXC controllers, too.
1: http://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/pentium-celeron-n-series-j-series-datasheet-spec-update.pdf
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