[PATCH net v2 3/3] r8152: Choose our USB config with choose_configuration() rather than probe()

Douglas Anderson
2023-12-01T18:31:50Z

If you deauthorize the r8152 device (by writing 0 to the "authorized"
field in sysfs) and then reauthorize it (by writing a 1) then it no
longer works. This is because when you do the above we lose the
special configuration that we set in rtl8152_cfgselector_probe().
Deauthorizing causes the config to be set to -1 and then reauthorizing
runs the default logic for choosing the best config.

I made an attempt to fix it so that the config is kept across
deauthorizing / reauthorizing [1] but it was a bit ugly.

Let's instead use the new USB core feature to override
choose_configuration().

This patch relies upon the patches ("usb: core: Don't force USB
generic_subclass drivers to define probe()") and ("usb: core: Allow
subclassed USB drivers to override usb_choose_configuration()")

[1] https://lore.kernel.org/r/20231130154337.1.Ie00e07f07f87149c9ce0b27ae4e26991d307e14b@changeid

Fixes: ec51fbd1b8a2 ("r8152: add USB device driver for config selection")
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

Changes in v2:
- ("Choose our USB config with choose_configuration()...) new for v2.

drivers/net/usb/r8152.c | 16 +++++-----------
1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index 2c5c1e91ded6..0da723d11326 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -10053,7 +10053,7 @@ static struct usb_driver rtl8152_driver = {
.disable_hub_initiated_lpm = 1,
};

-static int rtl8152_cfgselector_probe(struct usb_device *udev)
+static int rtl8152_cfgselector_choose_configuration(struct usb_device *udev)
{
struct usb_host_config *c;
int i, num_configs;
@@ -10080,19 +10080,13 @@ static int rtl8152_cfgselector_probe(struct usb_device *udev)
if (i == num_configs)
return -ENODEV;

- if (usb_set_configuration(udev, c->desc.bConfigurationValue)) {
- dev_err(&udev->dev, "Failed to set configuration %d\n",
- c->desc.bConfigurationValue);
- return -ENODEV;
- }
-
- return 0;
+ return c->desc.bConfigurationValue;
}

static struct usb_device_driver rtl8152_cfgselector_driver = {
- .name = MODULENAME "-cfgselector",
- .probe = rtl8152_cfgselector_probe,
- .id_table = rtl8152_table,
+ .name = MODULENAME "-cfgselector",
+ .choose_configuration = rtl8152_cfgselector_choose_configuration,
+ .id_table = rtl8152_table,
.generic_subclass = 1,
.supports_autosuspend = 1,
};
--
2.43.0.rc2.451.g8631bc7472-goog