> On 23 Nov 2017, at 3:58 PM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Thu, Nov 23, 2017 at 01:38:38AM -0500, Kai-Heng Feng wrote: >> r8153 on Dell TB dock corrupts rx packets. >> >> The root cause is not found yet, but disabling rx checksumming can >> workaround the issue. We can use this connection to decide if it's >> a Dell TB dock: >> Realtek r8153 <-> SMSC hub <-> ASMedia XHCI controller >> >> BugLink: https://bugs.launchpad.net/bugs/1729674 >> Cc: Mario Limonciello <mario.limonciello@xxxxxxxx> >> Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> >> --- >> drivers/net/usb/r8152.c | 33 ++++++++++++++++++++++++++++++++- >> 1 file changed, 32 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c >> index d51d9abf7986..58b80b5e7803 100644 >> --- a/drivers/net/usb/r8152.c >> +++ b/drivers/net/usb/r8152.c >> @@ -27,6 +27,8 @@ >> #include <linux/usb/cdc.h> >> #include <linux/suspend.h> >> #include <linux/acpi.h> >> +#include <linux/pci.h> >> +#include <linux/usb/hcd.h> >> >> /* Information for net-next */ >> #define NETNEXT_VERSION "09" >> @@ -5135,6 +5137,35 @@ static u8 rtl_get_version(struct usb_interface *intf) >> return version; >> } >> >> +/* Ethernet on Dell TB 15/16 dock is connected this way: >> + * Realtek r8153 <-> SMSC hub <-> ASMedia XHCI controller >> + * We use this connection to make sure r8153 is on the Dell TB dock. >> + */ >> +static bool check_dell_tb_dock(struct usb_device *udev) >> +{ >> + struct usb_device *hub = udev->parent; >> + struct usb_device *root_hub; >> + struct pci_dev *controller; >> + >> + if (!hub) >> + return false; >> + >> + if (!(le16_to_cpu(hub->descriptor.idVendor) == 0x0424 && >> + le16_to_cpu(hub->descriptor.idProduct) == 0x5537)) >> + return false; >> + >> + root_hub = hub->parent; >> + if (!root_hub || root_hub->parent) >> + return false; >> + >> + controller = to_pci_dev(bus_to_hcd(root_hub->bus)->self.controller); > > That's a very scary, and dangerous, cast. You can not ever be sure that > the hub really is a "root hub" like this. What I want to do here is to finding this connection: Realtek r8153 <-> SMSC hub (USD ID: 0424:5537) <-> ASMedia XHCI controller (PCI ID: 1b21:1142). Is there a safer way to do this? > >> + if (controller->vendor == 0x1b21 && controller->device == 0x1142) >> + return true; > > Why can't you just look at the USB device itself and go off of a quirk > in it? Something like a version or string or something else? I have a r8153 <-> USB 3.0 dongle which work just fine. I can’t find any information to differentiate them. Hence I want to use the connection to identify if r8153 is on a Dell TB dock. > > This sounds like a USB host controller issue, not a USB device issue, > can't we fix the "real" problem here instead of this crazy work-around? Yes. From what I know, ASMedia is working on it, but not sure how long it will take. In the meantime, I’d like to workaround this issue for the users. > Odds are any device plugged into the hub should have the same issue, > right? Actually no. I just plugged r8153 dongle into the same hub, surprisingly the issue doesn’t happen in this scenario. Kai-Heng > > thanks, > > greg k-h -- 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
