Hi all, I am not sure if this is the right way to ask a question about SD cards, so please correct me as I am new to Linux kernel development. I am currently working with a Intel Joule SOM and development board (Broxton M core) and when I insert the SD card, it is recognized as a SDR104 UHS-I card. Since this host has the MMC_CAP_AGGRESSIVE_PM bit set, it is suspended. That all works as expected. When the card is resumed, the OCR is read expecting bit 24 (switch to 1.8 V accepted (S18A)) to be set, but it is clear as the card is still at 1.8v signaling since it was never powered down during the suspend. I see 3 ways to solve this problem: First, power down the card during suspend. I think this is the intended behavior but there is no power manager registered to this host (as compiled) and I'm not sure how to add one, let alone the hardware changes necessary to implement the powering down of the sd card. Second, don't suspend (I have tested this and it works as the card is not suspended) Third, the host could remember that the card was at 1.8v signaling and if it will not "switch" to 1.8v, assume it is at 1.8v and go through the uhs_setup anyway. I have tried this too and it works for UHS cards, but I doubt it would be the right change. I would appreciate any help or direction anyone can provide as I would really like to use my fast card at the full data rates. I am currently setup to test any suggestions you have. Thank you all, -John -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
