Jack Pham wrote:

Hi Thinh,

On Fri, Jan 08, 2021 at 02:19:30AM +0000, Thinh Nguyen wrote:

quoted

Hi Wesley,

Felipe Balbi wrote:

quoted

Hi,

Wesley Cheng [off-list ref] writes:

quoted

+void composite_reset(struct usb_gadget *gadget)
+{
+	/*
+	 * Section 1.4.13 Standard Downstream Port of the USB battery charging
+	 * specification v1.2 states that a device connected on a SDP shall only
+	 * draw at max 100mA while in a connected, but unconfigured state.

The requirements are different, though. I think OTG spec has some extra
requirements where only 8mA can be drawn max. You need to check for the
otg flag. Moreover, USB3+ spec has units of 150mA meaning the device
can't draw 100mA (IIRC).

We see issue with this patch series. For our device running at SSP, the
device couldn't recover from a port reset and remained in eSS.Inactive
state.

This patch series is already in Greg's usb-testing. Please review and
help fix it.

We can see the failure once the patch "usb: gadget: configfs: Add a
specific configFS reset callback" is introduced.

Hmm. Does your device use a legacy USB2 PHY (not generic PHY) driver,
and does it implement the usb_phy_set_power() callback? Because
otherwise this new configfs_composite_reset() callback would not have
changed from the original behavior since the newly introduced (in patch
1/3) dwc3_gadget_vbus_draw() callback would simply be a no-op if
dwc->usb2_phy is not present.

If it does turn out to be something with your PHY driver's set_power(),
it's still puzzling since it's directed to only the usb2_phy, so I'm
curious how telling it to draw 100mA could affect SSP operation at all.

Thanks,
Jack

So, I ran some more tests. It seems like this new change affects some
timing in my setup that triggers this failure. I tried to add some
printouts to look into it further, but somehow that reduces the failure
rate significantly. This doesn't seem related to power drawing as it
doesn't update usb2_phy for SSP as you said.

After switching my HW setup, the problem seems to go away. I guess we
can ignore this since the code path looks to be the same as previous.

BR,
Thinh