Hi,
Alan Stern wrote:
> On Thu, 12 Dec 2019, Felipe Balbi wrote:
>
>> Hi,
>>
>> Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> writes:
>>> Introduce gadget opts udc_set_sublink_speed callback to set the lane
>>> count and transfer rate (in lane speed mantissa of Gbps) for SuperSpeed
>>> Plus capable gadgets. In the same way udc_set_speed, this function can
>>> control the gadget's sublink attributes for SuperSpeed Plus.
>>>
>>> Signed-off-by: Thinh Nguyen <thinhn@xxxxxxxxxxxx>
>>> ---
>>> drivers/usb/gadget/composite.c | 2 ++
>>> drivers/usb/gadget/legacy/mass_storage.c | 2 ++
>> I would rather not add new features to the legacy gadgets and focus on
>> our configfs interface for anything new. Moreover, using the feature
>> you introduced could, arguably, be done as a separate patch.
>>
>>> diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
>>> index 3b4f67000315..a4de5a8c0f19 100644
>>> --- a/drivers/usb/gadget/composite.c
>>> +++ b/drivers/usb/gadget/composite.c
>>> @@ -2353,6 +2353,8 @@ int usb_composite_probe(struct usb_composite_driver *driver)
>>> gadget_driver->function = (char *) driver->name;
>>> gadget_driver->driver.name = driver->name;
>>> gadget_driver->max_speed = driver->max_speed;
>>> + gadget_driver->max_lane_count = driver->max_lane_count;
>>> + gadget_driver->max_lsm = driver->max_lsm;
>>>
>>> return usb_gadget_probe_driver(gadget_driver);
>>> }
>>> diff --git a/drivers/usb/gadget/legacy/mass_storage.c b/drivers/usb/gadget/legacy/mass_storage.c
>>> index f18f77584fc2..a0912c5afffc 100644
>>> --- a/drivers/usb/gadget/legacy/mass_storage.c
>>> +++ b/drivers/usb/gadget/legacy/mass_storage.c
>>> @@ -223,6 +223,8 @@ static struct usb_composite_driver msg_driver = {
>>> .name = "g_mass_storage",
>>> .dev = &msg_device_desc,
>>> .max_speed = USB_SPEED_SUPER_PLUS,
>>> + .max_lane_count = 2,
>>> + .max_lsm = 10,
>> Right, as mentioned, I'd prefer not touch the legacy gadgets. But in any
>> case, why is it so that the gadget is telling you about max lane count
>> and lsm? That should be abstracted away from the gadget driver. Gadget
>> driver shouldn't have knowledge of number of lanes because, at the end
>> of the day, that doesn't really change anything in practice. Unlike HS
>> vs SS which changes a bunch of things.
> I agree completely. Furthermore, it isn't at all clear where those two
> numbers came from. Why would g-mass-storage care that lane_count <= 2
> and lsm <= 10?
>
> Alan Stern
>
Right, I'll remove this and update according to Felipe's suggestions.
Thanks,
Thinh
