Hi, > -----Original Message----- > From: Felipe Balbi [mailto:balbi@xxxxxx] > Sent: Monday, November 09, 2015 8:20 AM > To: John Youn <John.Youn@xxxxxxxxxxxx>; McCauley, Ben > <Ben.McCauley@xxxxxxxxxx>; gregkh@xxxxxxxxxxxxxxxxxxx > Cc: linux-usb@xxxxxxxxxxxxxxx; Schroeder, Jay <Jay.Schroeder@xxxxxxxxxx> > Subject: Re: [PATCH] USB: DCW3: GADGET: Set Correct Max Speed > > > Hi, > > John Youn <John.Youn@xxxxxxxxxxxx> writes: > > On 11/6/2015 9:55 AM, Felipe Balbi wrote: > >> > >> Hi, > >> > >> "McCauley, Ben" <Ben.McCauley@xxxxxxxxxx> writes: > >>> Felipe, > >>> > >>> -----Original Message----- > >>> From: Felipe Balbi [mailto:balbi@xxxxxx] > >>> Sent: Friday, November 06, 2015 10:06 AM > >>> To: McCauley, Ben <Ben.McCauley@xxxxxxxxxx> > >>> Cc: linux-usb@xxxxxxxxxxxxxxx; Schroeder, Jay > >>> <Jay.Schroeder@xxxxxxxxxx> > >>> Subject: Re: [PATCH] USB: DCW3: GADGET: Set Correct Max Speed > >>>> > >>>> > >>>> Hi, > >>>> > >>>> "McCauley, Ben" <Ben.McCauley@xxxxxxxxxx> writes: > >>>>> The max speed was always being set to USB_SUPER_SPEED even > when > >>>>> the phy was only capable of HIGH_SPEED. This > >>>> > >>>> this statement is untrue > >>>> > >>>>> uses the value set for the phy to set the max for the gadget. It > >>>>> resolves an issue with Window PCs where they report that using a > >>>>> USB3.0 port would result in better performance even when > >>>>> connecting through a 3.0 port. > >>>> > >>>> man, who gave you this kernel ? Which kernel version are you using ? > >>>> Have you even tested mainline ? > >>> > >>> This Kernel is from > >>> http://omapzoom.org/?p=kernel/omap.git;a=shortlog;h=refs/heads/p- > ti- > >>> linux-3.14.y-common at branch > >>> "development/omapzoom/glsdk-7.-2.00.02". > >>> I have not tested it on main line. > >> > >> seems like you should be talking to your FAE or using TI's e2e forum > >> for this. > >> > >>>>> Signed-off-by: McCauley, Ben <ben.mccauley@xxxxxxxxxx> > >>>>> --- > >>>>> > >>>>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c > >>>>> index 1eaf31c..0a388e3 100644 > >>>>> --- a/drivers/usb/dwc3/gadget.c > >>>>> +++ b/drivers/usb/dwc3/gadget.c > >>>>> @@ -2899,7 +2899,7 @@ > >>>> > >>>> which kernel are you using ? This file is 2868 lines, so you're > >>>> patching outside the file. > >>>> > >>>>> } > >>>>> > >>>>> dwc->gadget.ops = &dwc3_gadget_ops; > >>>>> - dwc->gadget.max_speed = USB_SPEED_SUPER; > >>>>> + dwc->gadget.max_speed = dwc->maximum_speed; > >>>> > >>>> this is corrected at dwc3_gadget_start(): > >> > >> and I see that in that kernel, this is corrected at > >> dwc3_gadget_restart() instead. > >> > >>>> /** > >>>> * WORKAROUND: DWC3 revision < 2.20a have an issue > >>>> * which would cause metastability state on Run/Stop > >>>> * bit if we try to force the IP to USB2-only mode. > >>>> * > >>>> * Because of that, we cannot configure the IP to any > >>>> * speed other than the SuperSpeed > >>>> * > >>>> * Refers to: > >>>> * > >>>> * STAR#9000525659: Clock Domain Crossing on DCTL in > >>>> * USB 2.0 Mode > >>>> */ > >>>> if (dwc->revision < DWC3_REVISION_220A) { > >>>> reg |= DWC3_DCFG_SUPERSPEED; > >>>> } else { > >>>> switch (dwc->maximum_speed) { > >>>> case USB_SPEED_LOW: > >>>> reg |= DWC3_DSTS_LOWSPEED; > >>>> break; > >>>> case USB_SPEED_FULL: > >>>> reg |= DWC3_DSTS_FULLSPEED1; > >>>> break; > >>>> case USB_SPEED_HIGH: > >>>> reg |= DWC3_DSTS_HIGHSPEED; > >>>> break; > >>>> case USB_SPEED_SUPER: /* FALLTHROUGH */ > >>>> case USB_SPEED_UNKNOWN: /* FALTHROUGH */ > >>>> default: > >>>> reg |= DWC3_DSTS_SUPERSPEED; > >>>> } > >>>> } > >>>> > >>> > >>> I am on 3.14 LTS though even on 4.3 I do not see > >>> dwc->gadget.max_speed being updated to reflect the actual max speed > >>> as set in drivers/usb/dwc3/core.c [dwc3_probe()]. > >>> dwc->gadget.max_speed is used in a number of locations to determine > >>> what response is sent to the host. > >>> > >>> dwc3_gadget_start() only appears to set the max speed to the > >>> register and not update the gadget. > >> > >> but the IP _is_ super-speed capable. Max speed should only be used to > >> determine if $this gadget can run with $this controller; speed, > >> instead, is used for all sorts of different things and _that_ is > >> updated on Connection Done IRQ. > >> > >> Can you point one place where you think it's wrong ? And, please, > >> refer to mainline code. We can't support a v3.14 kernel which might > >> contain a ton of additions which are not in mainline (for example, > >> mainline doesn't have a dwc3_gadget_restart() function). > >> > > > > > > Hi Felipe, > > > > There are 3 related speed settings which may be confusing the matter. > > > > dwc->maximum_speed > > > > A user-supplied parameter that determines how to program the > > DCFG.speed. This is the code you're referring to above. > > > > gadget->speed > > > > The current connected speed of the gadget. Used in various ways by the > > upper layer. > > > > gadget->max_speed > > > > Reports the maximum speed supported by the gadget. > > > > This is used by upper layer to determine which BOS descriptors to send > > and the settings within those descriptors. It's also used to set the > > bcdUSB appropriately. > > no, bcdUSB will be set to 0x0210 if max_speed == SUPER & speed == HIGH: > > case USB_DT_DEVICE: > cdev->desc.bNumConfigurations = > count_configs(cdev, USB_DT_DEVICE); > cdev->desc.bMaxPacketSize0 = > cdev->gadget->ep0->maxpacket; > if (gadget_is_superspeed(gadget)) { > if (gadget->speed >= USB_SPEED_SUPER) { > cdev->desc.bcdUSB = > cpu_to_le16(0x0300); > cdev->desc.bMaxPacketSize0 = 9; > } else { > cdev->desc.bcdUSB = > cpu_to_le16(0x0210); > } > } else { > cdev->desc.bcdUSB = cpu_to_le16(0x0200); > } > > > > Ben is talking about setting the gadget->max_speed, which is > > hard-coded in dwc3 to USB_SPEED_SUPER. > > > > For this core, the maximum supported speed may not actually be super > > speed. Many customers choose to use the 3.0 core in 2.0-only mode with > > a HS phy. > > yeah, I got all that. But we still have the problem of metastability for anything > <2.20a. For those cores, we just cannot mess around with any of these > settings (STAR 9000525659, if you wanna check). > > > And with the 3.1 core, it my be integrated in a system that is > > HS-only, SS (gen1), or SSP (gen2) capable. So the > > gadget->max_speed needs to be set correctly based on some > > user-defined or detected value. > > > > We have a similar change in our local tree for 3.1, except we set it > > based on GHWPARAMS3.SSPHY_INTERFACE. But I think it makes sense to > set > > it from dwc->maximum_speed as well, for testing or to override it. > > My other fear is about people setting this wrongly and later complaining that > it's not working. I would very much prefer your patch which detects whether > SSPHY_INTERFACE is around, however that won't always be correct. > > I just noticed that in our USB2-only SoC (AM437x), SSPHY_INTERFACE is set to > 1 even though this SoC does _not_ have any USB3 capabilities. > > GHWPARAMS3 = 0x10420085 > > I actually tested this problem as listed above and connected my USB2-only > SoC to a windows box (both USB2 and USB3 hosts) and did not see any such > error messages. Any ideas why you have problems an I don't ? Using an actual 3.0 device I have been able to generate the following message "This device can perform faster", when connecting to one of the 2.0 ports on the same PC. It might have something to do with the organization of the USB hubs In my computer making windows think that a 3.0 device was connected to a 2.0 when the reality is swapped when connecting the gadget. > > Maybe, all we have to do is avoid adding a SuperSpeed USB Capability > descriptor if we didn't negotiate for superspeed. All the rest can remain the > same: > > diff --git a/drivers/usb/gadget/composite.c > b/drivers/usb/gadget/composite.c index 8b14c2a13ac5..672ae6bfcad8 > 100644 > --- a/drivers/usb/gadget/composite.c > +++ b/drivers/usb/gadget/composite.c > @@ -547,9 +547,8 @@ static int count_configs(struct usb_composite_dev > *cdev, unsigned type) static int bos_desc(struct usb_composite_dev *cdev) > { > struct usb_ext_cap_descriptor *usb_ext; > - struct usb_ss_cap_descriptor *ss_cap; > - struct usb_dcd_config_params dcd_config_params; > struct usb_bos_descriptor *bos = cdev->req->buf; > + struct usb_gadget *gadget = cdev->gadget; > > bos->bLength = USB_DT_BOS_SIZE; > bos->bDescriptorType = USB_DT_BOS; > @@ -569,33 +568,38 @@ static int bos_desc(struct usb_composite_dev > *cdev) > usb_ext->bDevCapabilityType = USB_CAP_TYPE_EXT; > usb_ext->bmAttributes = cpu_to_le32(USB_LPM_SUPPORT | > USB_BESL_SUPPORT); > > - /* > - * The Superspeed USB Capability descriptor shall be implemented by > all > - * SuperSpeed devices. > - */ > - ss_cap = cdev->req->buf + le16_to_cpu(bos->wTotalLength); > - bos->bNumDeviceCaps++; > - le16_add_cpu(&bos->wTotalLength, USB_DT_USB_SS_CAP_SIZE); > - ss_cap->bLength = USB_DT_USB_SS_CAP_SIZE; > - ss_cap->bDescriptorType = USB_DT_DEVICE_CAPABILITY; > - ss_cap->bDevCapabilityType = USB_SS_CAP_TYPE; > - ss_cap->bmAttributes = 0; /* LTM is not supported yet */ > - ss_cap->wSpeedSupported = > cpu_to_le16(USB_LOW_SPEED_OPERATION | > + if (gadget->speed >= USB_SPEED_SUPER) { > + struct usb_ss_cap_descriptor *ss_cap; > + struct usb_dcd_config_params dcd_config_params; > + > + /* > + * The Superspeed USB Capability descriptor shall be > implemented > + * by all SuperSpeed devices. > + */ > + ss_cap = cdev->req->buf + le16_to_cpu(bos->wTotalLength); > + bos->bNumDeviceCaps++; > + le16_add_cpu(&bos->wTotalLength, > USB_DT_USB_SS_CAP_SIZE); > + ss_cap->bLength = USB_DT_USB_SS_CAP_SIZE; > + ss_cap->bDescriptorType = USB_DT_DEVICE_CAPABILITY; > + ss_cap->bDevCapabilityType = USB_SS_CAP_TYPE; > + ss_cap->bmAttributes = 0; /* LTM is not supported yet */ > + ss_cap->wSpeedSupported = > cpu_to_le16(USB_LOW_SPEED_OPERATION | > USB_FULL_SPEED_OPERATION | > USB_HIGH_SPEED_OPERATION | > USB_5GBPS_OPERATION); > - ss_cap->bFunctionalitySupport = USB_LOW_SPEED_OPERATION; > + ss_cap->bFunctionalitySupport = > USB_LOW_SPEED_OPERATION; > > - /* Get Controller configuration */ > - if (cdev->gadget->ops->get_config_params) > - cdev->gadget->ops- > >get_config_params(&dcd_config_params); > - else { > + /* Get Controller configuration */ > dcd_config_params.bU1devExitLat = > USB_DEFAULT_U1_DEV_EXIT_LAT; > dcd_config_params.bU2DevExitLat = > cpu_to_le16(USB_DEFAULT_U2_DEV_EXIT_LAT); > + > + if (cdev->gadget->ops->get_config_params) > + cdev->gadget->ops- > >get_config_params(&dcd_config_params); > + > + ss_cap->bU1devExitLat = dcd_config_params.bU1devExitLat; > + ss_cap->bU2DevExitLat = dcd_config_params.bU2DevExitLat; > } > - ss_cap->bU1devExitLat = dcd_config_params.bU1devExitLat; > - ss_cap->bU2DevExitLat = dcd_config_params.bU2DevExitLat; > > return le16_to_cpu(bos->wTotalLength); } > > Can you see if this solves the issue you're having ? > I can confirm that this does resolve Windows reporting a that a 3.0 device was connected to a non 3.0 port. I am concerned that though this fixes the issue, it could result in 3.0 devices not reporting themselves as a 3.0 device when connected to a 2.0 port. > -- > balbi ________________________________ CONFIDENTIALITY NOTICE: This email and any attachments are for the sole use of the intended recipient(s) and contain information that may be confidential and/or legally privileged. If you have received this email in error, please notify the sender by reply email and delete the message. Any disclosure, copying, distribution or use of this communication (including attachments) by someone other than the intended recipient is prohibited. Thank you. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
