On May 15 2017 or thereabouts, Ping Cheng wrote:
> On Fri, Mar 31, 2017 at 9:17 AM, Jason Gerecke <killertofu@xxxxxxxxx> wrote:
> > On 03/29/2017 12:30 AM, Benjamin Tissoires wrote:
> >> On Mar 28 2017 or thereabouts, Jason Gerecke wrote:
> >>> The 'wacom_update_name' function is responsible for producing names for
> >>> the input device nodes based on the hardware device name. Commit f2209d4
> >>> added the ability to strip off prefixes like "Wacom Co.,Ltd." where the
> >>> prefix was immediately (and redundantly) followed by "Wacom". The
> >>> 2nd-generation Intuos Pro 2 has such a prefix, but with a small error
> >>> (the period and comma are swapped) that prevents the existing code from
> >>> matching it. We're loath to extend the number of cases out endlessly and
> >>> so instead try to be smarter about name generation.
> >>>
> >>> We observe that the cause of the redundant prefixes is HID combining the
> >>> manufacturer and product strings of USB devices together. By using the
> >>> original product name (with "Wacom" prefixed, if it does not already
> >>> exist in the string) we can bypass the gyrations to find and remove
> >>> redundant prefixes. For devices connected by other busses, the problem
> >>> either doesn't exist (e.g. BUS_BLUETOOTH) or the name should be replaced
> >>> with a generic one entirely (e.g. BUS_I2C, BUS_INTEL_ISHTP).
> >>
> >> Ouch. I hope Wacom doesn't plan on using BUS_INTEL_ISHTP for new devices
> >> :)
> >>
> >
> > Just me parroting bus names at random. Perhaps BUS_INTEL_ISHTP wasn't a
> > great example ;)
> >
> >>>
> >>> Signed-off-by: Jason Gerecke <jason.gerecke@xxxxxxxxx>
> >>> ---
> >>> drivers/hid/wacom_sys.c | 65 +++++++++++++++++++++++++------------------------
> >>> 1 file changed, 33 insertions(+), 32 deletions(-)
> >>>
> >>> diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
> >>> index 037b9c04745a..ad5d8722fa84 100644
> >>> --- a/drivers/hid/wacom_sys.c
> >>> +++ b/drivers/hid/wacom_sys.c
> >>> @@ -2026,41 +2026,42 @@ static void wacom_update_name(struct wacom *wacom, const char *suffix)
> >>>
> >>> /* Generic devices name unspecified */
> >>> if ((features->type == HID_GENERIC) && !strcmp("Wacom HID", features->name)) {
> >>> - if (strstr(wacom->hdev->name, "Wacom") ||
> >>> - strstr(wacom->hdev->name, "wacom") ||
> >>> - strstr(wacom->hdev->name, "WACOM")) {
> >>> - /* name is in HID descriptor, use it */
> >>> - strlcpy(name, wacom->hdev->name, sizeof(name));
> >>> -
> >>> - /* strip out excess whitespaces */
> >>> - while (1) {
> >>> - char *gap = strstr(name, " ");
> >>> - if (gap == NULL)
> >>> - break;
> >>> - /* shift everything including the terminator */
> >>> - memmove(gap, gap+1, strlen(gap));
> >>> - }
> >>> + char *product_name = NULL;
> >>>
> >>> - /* strip off excessive prefixing */
> >>> - if (strstr(name, "Wacom Co.,Ltd. Wacom ") == name) {
> >>> - int n = strlen(name);
> >>> - int x = strlen("Wacom Co.,Ltd. ");
> >>> - memmove(name, name+x, n-x+1);
> >>> - }
> >>> - if (strstr(name, "Wacom Co., Ltd. Wacom ") == name) {
> >>> - int n = strlen(name);
> >>> - int x = strlen("Wacom Co., Ltd. ");
> >>> - memmove(name, name+x, n-x+1);
> >>> - }
> >>> + if (wacom->hdev->bus == BUS_USB) {
> >>> + struct usb_interface *intf = to_usb_interface(wacom->hdev->dev.parent);
> >>> + struct usb_device *dev = interface_to_usbdev(intf);
> >>> + product_name = dev->product;
> >>
> >> This will break uhid emulated devices in a very bad way (oops).
> >> How about you either add a stub to get the product name from the
> >> low-level driver, or simply add 2 pointers to strings to store the
> >> product_name and the vendor_name in struct hid_device?
> >>
> >
> > Good call on the uhid emulation. I'll write up an alternate patch as
> > suggested. Do you have any particular preference either way? I suppose
> > the former would be more amenable to the extra credit, but...
>
> Since Benjamin didn't have a preference (he didn't reply so I assumed
> the answer ;), I think you can update the patch with your own choice.
>
> >
> >> Bonus point if you let hid-core decide on the name based on the vendor
> >> ID with a table of commonly used companies. hid-core could also clean up
> >> the product name so you won't have to do it in each HID driver.
> >> The choice of using a weird name for I2C devices was a lazy one from me,
> >> and I am starting to hope for something better in the future.
> >>
> >> Cheers,
> >> Benjamin
> >>
> >
> > ...I probably won't go for the extra-credit here. Our driver seems to be
> > pretty unique in how it tries to prettify the vendor; others either
> > replace the name wholesale (like we do in the non-generic codepath) or
> > just append suffixes where necessary.
>
> I agree. I don't think it is necessary to touch hid-core.
Yeah, sorry, this email went deep into my mailbox. A hid-core cleanup
would be nice, but if you are the only one in need for that, then you
can have a special case in your module.
Cheers,
Benjamin
>
> Cheers,
> Ping
>
> >
> > Jason
> > ---
> > Now instead of four in the eights place /
> > you’ve got three, ‘Cause you added one /
> > (That is to say, eight) to the two, /
> > But you can’t take seven from three, /
> > So you look at the sixty-fours....
> >
> >>> + }
> >>> + else if (wacom->hdev->bus == BUS_BLUETOOTH) {
> >>> + product_name = wacom->hdev->name;
> >>> + }
> >>>
> >>> - /* get rid of trailing whitespace */
> >>> - if (name[strlen(name)-1] == ' ')
> >>> - name[strlen(name)-1] = '\0';
> >>> - } else {
> >>> - /* no meaningful name retrieved. use product ID */
> >>> - snprintf(name, sizeof(name),
> >>> - "%s %X", features->name, wacom->hdev->product);
> >>> + if (!product_name) {
> >>> + snprintf(name, sizeof(name), "%s %X",
> >>> + features->name, wacom->hdev->product);
> >>> }
> >>> + else if (strstr(product_name, "Wacom") ||
> >>> + strstr(product_name, "wacom") ||
> >>> + strstr(product_name, "WACOM")) {
> >>> + strlcpy(name, product_name, sizeof(name));
> >>> + }
> >>> + else {
> >>> + snprintf(name, sizeof(name), "Wacom %s", product_name);
> >>> + }
> >>> +
> >>> + /* strip out excess whitespaces */
> >>> + while (1) {
> >>> + char *gap = strstr(name, " ");
> >>> + if (gap == NULL)
> >>> + break;
> >>> + /* shift everything including the terminator */
> >>> + memmove(gap, gap+1, strlen(gap));
> >>> + }
> >>> +
> >>> + /* get rid of trailing whitespace */
> >>> + if (name[strlen(name)-1] == ' ')
> >>> + name[strlen(name)-1] = '\0';
> >>> } else {
> >>> strlcpy(name, features->name, sizeof(name));
> >>> }
> >>> --
> >>> 2.12.0
> >>>
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