Re: [PATCH] usb: host: tegra: Reset Tegra USB controller before init
From: Stephen Warren
Date: Thu Feb 28 2013 - 13:10:33 EST
On 02/28/2013 08:09 AM, Alan Stern wrote:
> On Thu, 28 Feb 2013, Venu Byravarasu wrote:
>> To clear any configurations made by U-Boot on Tegra USB controller,
>> reset it before init in probe.
>> Signed-off-by: Venu Byravarasu <vbyravarasu@xxxxxxxxxx>
>> When U-Boot configures a Tegra USB controller in device mode and if the EHCI
>> driver of kernel tries to set it to HOST mode, message "irq 52: nobody cared"
>> appears and IRQ gets disabled.
>> This issue was initially reported with: http://marc.info/?l=linux-tegra&m=136110175423601&w=2
>> To avoid such issues, due to configurations made by U-Boot driver, reset the
>> Tegra USB controller, before configuring it by kernel.
> Does the Tegra platform use shared interrupts? If it does, what
> happens if the IRQ is enabled and in use by another device before
> ehci-tegra resets the USB controller?
I believe there's a dedicated interrupt just for each individual controller.
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