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...
> 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.
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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