12-19-2009, 06:41 PM | #1 |
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Device: Kindle DX
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serial console goes to sleep - gated clock
Does anyone happen to know how to keep the serial console from going to sleep after a bit of inactivity? At some point I see a message that the UART clock's been gated, and then only the Kindle side can wake it up again.
It's obviously some power management thing. Has anyone seen a setting for that someplace? Even better would be another IO line like DTR or RTS that would wake it up. Also, is there any GPIO-like unused pin anyplace that the system has access to? |
12-19-2009, 06:45 PM | #2 |
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Here's the actual sleep msg:
uart: I def:clk gate::uart clk gated |
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12-19-2009, 08:52 PM | #3 |
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I found it in the kernel sources, and it's controlled by a device attribute at /sys/devices/platform/mxcintuart.0/uart_clk_state. Set it to 0, and it won't gate.
I was about to write an init.d script to do that for me, but I found something in /etc/init.d/power that does that for you. You just need to create a file called DO_NOT_KILL_UART in /mnt/us. |
Tags |
hack, hardware, kindle dx |
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