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pepe2k / u-boot_mod

U-Boot 1.1.4 modification for routers
GNU General Public License v2.0
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Should USB Configuration Control Register be set by u-boot? #221

Closed phizev closed 5 years ago

phizev commented 5 years ago

I've been looking into why the USB speed on my WDR3600 has been slow for quite a while, and I'm not sure if the original firmware had this issue or not. The integrated hub is a USB2.0 hub. After much reading, I think the issue may be due to the USB_CONFIG registers not enabling high speed mode. Register table is at 9.3.2 on page 161 in https://github.com/Deoptim/atheros/blob/master/AR9344_May_2012.pdf

I'm not sure whom is responsible for setting these registers, if I know whether it should be done by u-boot, or by the Linux kernel/driver, it will help a lot with my further attempts to find a fix.

pepe2k commented 5 years ago

I'm not sure whom is responsible for setting these registers, if I know whether it should be done by u-boot, or by the Linux kernel/driver, it will help a lot with my further attempts to find a fix.

It's enabled by default (check the reset value of that register).

Cheers, Piotr

phizev commented 5 years ago

Ah, thanks! I learned something very useful about what the reset value actually is, it's bypassed me thus far.

phizev commented 5 years ago

To follow up on this, the slow USB speed seems to be entirely related to using the ath79 device tree platform of OpenWRT, instead of the older ar71xx platform for my TP-Link WDR3600. The kernel did put out a warning on ath79 that the device was operating in full speed mode, instead of high speed mode. I have not found a way to fix this on ath79 yet.

Using the ar71xx platform has High Speed/USB2 working correctly, as evidenced by the difference in throughput.