Enable ddr modes on emmc2 of Raspberry Pi 4 B
stefan.wahren at i2se.com
Mon Aug 31 07:32:30 EDT 2020
thanks for providing this patch to lkml . I sent a very similiar one
 to linux-mmc after the investigations on the Raspberry Pi github .
Can you please explain why this sd-uhs-ddr50 property is necessary?
From my testings with a UHS SD card the UHS DDR50 mode is already
properly configured before your patch.
Is there a specific combination which doesn't work?
Please provide the ios settings of /sys/kernel/debug/mmc1/ios in this
case before applying your patch.
 - https://marc.info/?l=linux-mmc&m=159865133820037
 - https://github.com/raspberrypi/linux/issues/3802
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