Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
Get HideMyAss! VPN, PC Mag's Top 10 VPNs of 2016 for 55% off for a Limited Time ×

Submission + - Full DMA access for USB-OTG on PPC405EX (huntercobbs.com)

hcob$ writes: "I'm doing some early prototying of a AMCC PPC405EX based board. Here's just a few of my actions so far to let you know how much frustration this one little problem has casued me:

        * Fixed the broken OpenWRT support for the AMCC Kilauea Dev Board with patches, backports and Makefile Modification
        * Ported DENX deployed USB-OTG support with the dwc_otg driver
        * Reworked the flash map so that there is a custom fall-back ramdisk and a fully-permenant rootfs

Then comes the next problem. After finally porting in the dwc_otg USB driver to the OpenWRT patched kernel, I went about hooking up some usb-serial devices that we planned to use. They detected properly and registered. The I open up a minicom connection and WAM! 99-100% IRQ usage. Completely bogged down the system. Turns out, the device is running in an IRQ(Slave) mode and triggering interrupts that need to be serviced at an insane rate (had a back log of 89k interrupts at some points). After two weeks of focusing on this problem, I finally noticed something odd in my kernel build."

Slashdot Top Deals

"It says he made us all to be just like him. So if we're dumb, then god is dumb, and maybe even a little ugly on the side." -- Frank Zappa