On 08.03.2022 15:55, Mathias Nyman wrote:
> On 4.3.2022 20.37, Heiner Kallweit wrote:
>> If either of the root hubs has no ports, then we can get rid of
>> overhead like the shared hcd. A major internal change is that now
>> the main hcd can be USB2 or USB3.
>>
>> Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
>> ---
>> drivers/usb/host/xhci-mem.c | 11 +++++------
>> drivers/usb/host/xhci.c | 9 ++++++---
>> 2 files changed, 11 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
>> index a1a17713a..ced139583 100644
>> --- a/drivers/usb/host/xhci-mem.c
>> +++ b/drivers/usb/host/xhci-mem.c
>> @@ -2362,12 +2362,11 @@ static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
>> xhci->usb2_rhub.num_ports = USB_MAXCHILDREN;
>> }
>>
>> - xhci->needs_shared_hcd = 1;
>> -
>> - /*
>> - * Note we could have all USB 3.0 ports, or all USB 2.0 ports.
>> - * Not sure how the USB core will handle a hub with no ports...
>> - */
>> + if (xhci->usb2_rhub.num_ports && xhci->usb3_rhub.num_ports)
>> + xhci->needs_shared_hcd = 1;
>> + else
>> + xhci_info(xhci, "USB%u root hub has no ports\n",
>> + xhci->usb2_rhub.num_ports ? 3 : 2);
>
> This now works for xhci controllers using xhci-plat.c, but in all other cases
> the the secondary hcd will still be added.
>
> Would it make sense to instead of setting xhci->needs_shared_hcd, we
> set a xhci->allow_single_roothub flag in the .reset override function?
> In the xhci-plat.c case this would be in xhci_plat_setup()
>
> We would only add the flag if the respective probe supports one roothub.
>
> Add a helper function to check if we if really should set up just one
> hcd in probe, and should call xhci_run_finished() already the he first time
> xhci_run() is called (like you do in patch 3/5).
>
> Something like:
>
> bool xhci_has_one_roothub(struct xhci_hcd *xhci)
> {
> return xhci->allow_single_roothub && (!xhci->usb2_rhub.num_ports != !xhci->usb3_rhub.num_ports);
> }
Looks (very) good to me. I'll incorporate this and reorder the patches,
then I'll send a v2.
>
> Thanks
> -Mathias
Heiner
