Comment 8 for bug 1735099

The linked github repository doesn't break out whatever the fix is to the rtsx_pci driver is. Therefore it is all but impossible to figure out what was changed.

Another user reported this today with 5.0.0-27-generic where 64GB cards are readable but 256GB cards are not. It isn't clear if the power-signalling errors are critical or incidental:

Sep 15 11:55:59 kubuntu-laptop kernel: mmc0: cannot verify signal voltage switch
Sep 15 11:56:00 kubuntu-laptop kernel: mmc0: new ultra high speed SDR104 SDXC card at address 0001
Sep 15 11:56:00 kubuntu-laptop kernel: mmcblk0: mmc0:0001 GC2QT 59.6 GiB
Sep 15 11:56:00 kubuntu-laptop kernel: mmcblk0: p1
Sep 15 11:57:06 kubuntu-laptop kernel: mmc0: card 0001 removed
Sep 15 11:57:14 kubuntu-laptop kernel: mmc0: cannot verify signal voltage switch
Sep 15 11:57:14 kubuntu-laptop kernel: mmc0: tuning execution failed: -22
Sep 15 11:57:14 kubuntu-laptop kernel: mmc0: error -22 whilst initialising SD card
Sep 15 11:57:15 kubuntu-laptop kernel: mmc0: error -110 whilst initialising SD card
Sep 15 11:57:17 kubuntu-laptop kernel: mmc0: cannot verify signal voltage switch
Sep 15 11:57:17 kubuntu-laptop kernel: mmc0: tuning execution failed: -22
Sep 15 11:57:17 kubuntu-laptop kernel: mmc0: error -22 whilst initialising SD card
Sep 15 11:58:08 kubuntu-laptop kernel: mmc0: cannot verify signal voltage switch
Sep 15 11:58:08 kubuntu-laptop kernel: mmc0: new ultra high speed SDR104 SDXC card at address 0001
Sep 15 11:58:08 kubuntu-laptop kernel: mmcblk0: mmc0:0001 GC2QT 59.6 GiB
Sep 15 11:58:08 kubuntu-laptop kernel: mmcblk0: p1
Sep 15 11:58:46 kubuntu-laptop kernel: mmc0: card 0001 removed