From mboxrd@z Thu Jan 1 00:00:00 1970 From: Larry Finger Subject: Help with writing to micro SD card Date: Thu, 14 May 2015 15:03:02 -0500 Message-ID: <5554FF76.2010206@lwfinger.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-kernel-owner@vger.kernel.org To: "linux-mmc@vger.kernel.org" , LKML Cc: Benny Silberstein , "peretz@benchmarkmerchantsolutions.com >> Peretz Mockin" List-Id: linux-mmc@vger.kernel.org I am helping to get wifi and Bluetooth woring under Linux using a Winbook TW100 tablet. The main goal is working quite well; however, I am only able to run using Live media. Whenever I try to load Linux onto either the internal SD card, or one mounted in the external slot, the process stalls with nothing logged. I know the external card is OK as I can read or write it when it is mounted in my laptop. When I received the tablet, I used dd to back up the internal card. When I used a block size of 4M in that operation, it also froze; however, the standard block size (512) worked. That suggests that the standard Linux r/w operations on the device are too fast. What should I do to get some debug information? If my idea is correct, how might I slow down the I/O to the device? Thanks, Larry