Bug 6578

Summary: SD DDR50 support should be disabled by default in the BIOS settings
Product: [Hardware Platforms] MinnowBoard MAX Firmware Reporter: Ivan Rouzanov <ivan.rouzanov>
Component: minnowmax-edk2Assignee: He, Tim <tim.he>
Status: RESOLVED FIXED QA Contact:
Severity: normal    
Priority: Low CC: sjolley.yp.pm, warthog9
Version: unspecified   
Target Milestone: Production Release   
Hardware: MinnowBoard Max   
OS: x86_64   
Whiteboard:
OS type for building Yocto: --- Type of Regression: ---
Verified: Documentation change: Don't know

Description Ivan Rouzanov 2014-07-25 17:21:53 UTC 
Due to the known errata in E3800 SD card support, UHS-I might not work correctly. The suggestion is to make DDR50 support disabled by default in order to reduce the chance for a negative experience for the user/reduce support request volume.


http://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/atom-e3800-family-spec-update.pdf

" SD Card UHS-I Mode is Not Fully Supported
Problem: The SD Card Specification rev 3.01 Addendum 1 specifies a relaxed NCRC (Number of clocks to Cyclic Redundancy Check) timing specification for UHS-I (DDR50) mode. Due to this erratum, the SD Host Controller is not fully compatible with this relaxed timing specification.
Implication: Using UHS-I mode with SD devices that rely upon relaxed NCRC may cause SD host commands to fail to complete, resulting in device access failures. "
Comment 1 John 'Warthog9' Hawley 2014-08-04 05:31:26 UTC 
IS there a way we can disable this from the UEFI shell for testing?  I've got an UHS-I card that's behaving oddly under Linux, and I'd like to try disabling this and seeing if it resolves the issue.
Comment 2 He, Tim 2014-08-04 08:04:09 UTC 
Yes, you can disable by setup page, please select "Device Manager -> System Setup -> South Cluster Configuration -> Lpss and Scc Configuration -> SD DDR50" to disable it.
Comment 3 John 'Warthog9' Hawley 2014-08-04 20:13:37 UTC 
ok that's working better, I'll try and get that mentioned on the wiki
Comment 4 He, Tim 2014-08-07 06:35:42 UTC 
The "SD DDR50" item on setup pages is disabled by default.