Hi Magnus-san,

(2014/10/29 15:53), Magnus Damm wrote:

On Fri, Oct 24, 2014 at 7:41 PM, Yoshihiro Shimoda
[off-list ref] wrote:

quoted

Since the PHY of USB3.0 and EHCI/OHCI ch2 are the same, the USB3.0
driver cannot use the phy driver when the EHCI/OHCI ch2 already used it:

phy phy-e6590100.usb-phy.3: phy init failed --> -16
xhci-hcd: probe of ee000000.usb failed with error -16

If so, we have to unbind the EHCI/OHCI ch2, and then we have to bind
the USB3.0 driver as the following:

  echo 0000:02:02.0 > /sys/bus/pci/drivers/ehci-pci/unbind
  echo 0000:02:01.0 > /sys/bus/pci/drivers/ohci-pci/unbind
  echo ee000000.usb > /sys/bus/platform/drivers/xhci-hcd/bind

Note that there will be pinctrl-related error messages if both
internal PCI and USB3.0 are enabled but they should be just ignored:

sh-pfc e6060000.pfc: pin GP_5_22 already requested by ee0d0000.pci; cannot claim for ee000000.usb
sh-pfc e6060000.pfc: pin-182 (ee000000.usb) status -22
ata1: SATA link down (SStatus 0 SControl 300)
sh-pfc e6060000.pfc: could not request pin 182 (GP_5_22) from group usb2  on device sh-pfc

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
---
 arch/arm/boot/dts/r8a7790-lager.dts |    6 ++++++
 1 file changed, 6 insertions(+)

Hi Shimoda-san,

Thanks for your patch. I'm fine with this patch as a first step, but
I'm wondering what the reason is to prioritize USB 2.0 over USB 3.0?

I investigated this reason today, and I found the reason is request_firmware().
I checked the following environments:

 Case 1: xHCI and EHCI and OHCI are enabled "=y"
 Case 2: xHCI and EHCI and OHCI are loadable modules "=m"
 Case 3: xHCI and EHCI and OHCI are enabled "=y", and CONFIG_EXTRA_FIRMWARE is enabled

The results are:
 - In "Case 1", EHCI and OHCI are probed first because xHCI didn't find the firmware.
 - In "Case 2" and "Case 3", xHCI is probed first.

Is the current order just based on device init order? In my mind the
expected behavior would be to always use USB 3.0 if it happens to be
available in the hardware, specified in the DTS, enabled by the kernel
configuration and firmware is loadable. Or does some case exist where
it is better to use USB 2.0? I suspect no.

I agree with you.

So I wonder if you have any plans how to make USB 3.0 enabled by
default on Lager?

It depends on a kernel config. I'm not sure of the shmobile_defconfig strategy.
But, in my opinion, one of a solution is kernel modules (this means the "Case 2".)

Best regards,
Yoshihiro Shimoda

Thanks,

/ magnus