On May 17 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. Other devices either don't have a manufacturer string
> that needs to be removed (Bluetooth, uhid) or should have their name
> generated from scratch (I2C).
>
> Signed-off-by: Jason Gerecke <jason.gerecke@xxxxxxxxx>
> ---
Thanks Jason.
I am not a big fan of the "real USB" check (I would believe enhancing
struct hid_device would make something more generic), but it seems to be
doing the job OK.
Just giving out 2 ideas to achieve the same, so you could decide keeping
this or not:
- adding .product_name to struct hid_device directly
- exporting usb_hid_driver in usbhid/usbhid.h and comparing hdev->ll_driver
with it (this can be achieved in an inlined function in usbhid.h).
I would believe having the second option above would provide several
benefits:
- the wacom module will not have to check against all usb devices
- other drivers would be able to quickly tell if they are using a low
level USB device, and not a uhid one. This way, we can remove some
errors when we emulate a HID device on a HID driver that expects USB
to be the actual transport layer
Your function works too, but I would believe this will be faster and
better (I also get the concern of having something self consistent for
easier backporting).
Besides that, small nitpicks:
> drivers/hid/wacom_sys.c | 90 ++++++++++++++++++++++++++++++++-----------------
> 1 file changed, 60 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
> index 838c1ebfffa9..c68458e44139 100644
> --- a/drivers/hid/wacom_sys.c
> +++ b/drivers/hid/wacom_sys.c
> @@ -14,6 +14,7 @@
> #include "wacom_wac.h"
> #include "wacom.h"
> #include <linux/input/mt.h>
> +#include <linux/usb.h>
>
> #define WAC_MSG_RETRIES 5
> #define WAC_CMD_RETRIES 10
> @@ -2020,6 +2021,29 @@ static size_t wacom_compute_pktlen(struct hid_device *hdev)
> return size;
> }
>
> +
> +static int __wacom_is_usb_parent(struct usb_device *usbdev, void *ptr)
> +{
> + struct wacom *wacom = ptr;
> + struct device *parent = wacom->hdev->dev.parent;
> + struct usb_host_config *config = usbdev->actconfig;
> + int i;
> +
> + for (i = 0; i < config->desc.bNumInterfaces; i++) {
> + if (&config->interface[i]->dev == parent)
> + return 1;
> + }
> + return 0;
> +}
> +
> +/*
> + * Distinguish between real USB devices and uhid-created doppelgangers
> + */
> +static bool wacom_is_real_usb(struct wacom *wacom) {
> + return wacom->hdev->bus == BUS_USB &&
> + usb_for_each_dev(wacom, __wacom_is_usb_parent);
> +}
> +
> static void wacom_update_name(struct wacom *wacom, const char *suffix)
> {
> struct wacom_wac *wacom_wac = &wacom->wacom_wac;
> @@ -2028,41 +2052,47 @@ 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 (wacom->hdev->bus == BUS_USB) {
> + if (wacom_is_real_usb(wacom)) {
wacom_is_real_usb() already checks for BUS_USB, so the first test is
redundant.
> + struct usb_interface *intf = to_usb_interface(wacom->hdev->dev.parent);
> + struct usb_device *dev = interface_to_usbdev(intf);
> + product_name = dev->product;
> }
> - 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);
> + else {
this else shoule be on the previous line
> + product_name = wacom->hdev->name;
> }
> + }
> + else if (wacom->hdev->bus == BUS_BLUETOOTH) {
likewise
> + product_name = wacom->hdev->name;
> + }
How about?:
if (wacom_is_real_usb(wacom)) {
struct usb_interface *intf = to_usb_interface(wacom->hdev->dev.parent);
struct usb_device *dev = interface_to_usbdev(intf);
product_name = dev->product;
} else if (wacom->hdev->bus == BUS_BLUETOOTH ||
wacom->hdev->bus == BUS_USB) {
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") ||
else should be on the previous line
> + 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));
> }
> --
> 2.12.2
>
Cheers,
Benjamin
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