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X-CSE-ConnectionGUID: J16sbjpHSASZtiPBrNBYdA== X-CSE-MsgGUID: kTzp60oVSyu4ep66+MrQDA== X-IronPort-AV: E=McAfee;i="6800,10657,11580"; a="61685688" X-IronPort-AV: E=Sophos;i="6.19,225,1754982000"; d="scan'208";a="61685688" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Oct 2025 02:01:41 -0700 X-CSE-ConnectionGUID: dVyeZaB2SKaGShqosdwBqQ== X-CSE-MsgGUID: NdkeTBpnQ2W5zOclVx1OeQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,225,1754982000"; d="scan'208";a="212176282" Received: from klitkey1-mobl1.ger.corp.intel.com (HELO [10.245.244.60]) ([10.245.244.60]) by orviesa002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Oct 2025 02:01:39 -0700 Message-ID: Date: Mon, 13 Oct 2025 12:01:37 +0300 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 3/4] xhci: dbc: allow to set product name through sysfs To: =?UTF-8?Q?=C5=81ukasz_Bartosik?= , Mathias Nyman , Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org References: <20251007213902.2231670-1-ukaszb@google.com> <20251007213902.2231670-4-ukaszb@google.com> Content-Language: en-US From: Mathias Nyman In-Reply-To: <20251007213902.2231670-4-ukaszb@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 10/8/25 00:39, Łukasz Bartosik wrote: > From: Łukasz Bartosik > > Add code which allows to set product name of a DbC > device through sysfs. > > Signed-off-by: Łukasz Bartosik > --- > .../testing/sysfs-bus-pci-drivers-xhci_hcd | 11 ++++++ > drivers/usb/host/xhci-dbgcap.c | 36 +++++++++++++++++++ > 2 files changed, 47 insertions(+) > > diff --git a/Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd b/Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd > index 071688dbd969..57ba37606f79 100644 > --- a/Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd > +++ b/Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd > @@ -98,3 +98,14 @@ Description: > The default value is "0001". > The field length can be from 1 to 63 characters. > > +What: /sys/bus/pci/drivers/xhci_hcd/.../dbc_iProduct > +Date: October 2025 > +Contact: Łukasz Bartosik > +Description: > + The dbc_iProduct attribute allows to change the iProduct field > + presented in the USB device descriptor by xhci debug device. > + Value can only be changed while debug capability (DbC) is in > + disabled state to prevent USB device descriptor change while > + connected to a USB host. > + The default value is "Linux USB Debug Target". > + The field length can be from 1 to 63 characters. > diff --git a/drivers/usb/host/xhci-dbgcap.c b/drivers/usb/host/xhci-dbgcap.c > index 7ad83548ba4d..bc782f6b533e 100644 > --- a/drivers/usb/host/xhci-dbgcap.c > +++ b/drivers/usb/host/xhci-dbgcap.c > @@ -1200,6 +1200,40 @@ static ssize_t dbc_bcdDevice_store(struct device *dev, > return size; > } > > +static ssize_t dbc_iProduct_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct xhci_hcd *xhci = hcd_to_xhci(dev_get_drvdata(dev)); > + struct xhci_dbc *dbc = xhci->dbc; > + > + return sysfs_emit(buf, "%s\n", dbc->str.product); > +} > + > +static ssize_t dbc_iProduct_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t size) > +{ > + struct xhci_hcd *xhci = hcd_to_xhci(dev_get_drvdata(dev)); > + struct xhci_dbc *dbc = xhci->dbc; > + size_t len; > + > + if (dbc->state != DS_DISABLED) > + return -EBUSY; > + > + len = strcspn(buf, "\n"); > + if (!len) > + return -EINVAL; > + > + if (len > USB_MAX_STRING_LEN/2) > + return -E2BIG; > + > + memcpy(dbc->str.product, buf, len); > + dbc->str.product[len] = '\0'; > + > + return size; > +} > + > static ssize_t dbc_iSerial_show(struct device *dev, > struct device_attribute *attr, > char *buf) > @@ -1321,6 +1355,7 @@ static DEVICE_ATTR_RW(dbc); > static DEVICE_ATTR_RW(dbc_idVendor); > static DEVICE_ATTR_RW(dbc_idProduct); > static DEVICE_ATTR_RW(dbc_bcdDevice); > +static DEVICE_ATTR_RW(dbc_iProduct); > static DEVICE_ATTR_RW(dbc_iSerial); > static DEVICE_ATTR_RW(dbc_bInterfaceProtocol); > static DEVICE_ATTR_RW(dbc_poll_interval_ms); > @@ -1330,6 +1365,7 @@ static struct attribute *dbc_dev_attrs[] = { > &dev_attr_dbc_idVendor.attr, > &dev_attr_dbc_idProduct.attr, > &dev_attr_dbc_bcdDevice.attr, > + &dev_attr_dbc_iProduct.attr, Small naming thing again. "dbc_idProduct" and dbc_iProduct" are a bit too similar. Usb core uses "product" and "manufacturer" sysfs entries to show these strings. I think dbc should use similar "dbc_product" and "dbc_manufacturer" naming. the "iProduct" is a byte in device descriptor telling the index of the product string descriptor. Thanks Mathias