For any Linux system using the BCM57765/57785 SDXC/MMC reader, do the following to fix mounting & reading SD cards:

1. Add a comand to /etc/rc.local:

   sudo nano /etc/rc.local     # add the following line above "exit 0"

   setpci -s 00:1c.2 0x50.B=0x41

2. Add the same comand to /etc/apm/resume.d/21aspm (which does not exist yet):

   sudo nano /etc/apm/resume.d/21aspm

   setpci -s 00:1c.2 0x50.B=0x41

3. Add a line to /etc/modprobe.d/sdhci (which may not exist yet):

   sudo nano /etc/modprobe.d/sdhci     # add the following to this file

   # For BCM57765/57785 SDXC/MMC reader
   options sdhci debug_quirks2=4

4. run the follwing command to regenerate initrd:

   sudo update-initramfs -u -k all

5. RESTART SYSTEM

References:

• https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1307674
  • follow the 3-step “WORKAROUND:” at the top of that page.
• https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1178131
  • edit the 2 files per comment #46