From fc85c59b85d111f51b58ecf08485fa74ac5471cd Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Mon, 28 Aug 2023 17:43:04 +0200 Subject: usb: gadgetfs: return USB_GADGET_DELAYED_STATUS from setup() Return USB_GADGET_DELAYED_STATUS from the setup() callback for 0-length transfers as a workaround to stop some UDC drivers (e.g. dwc3) from automatically proceeding with the status stage. This workaround should be removed once all UDC drivers are fixed to always delay the status stage until a response is queued to EP0. Reviewed-by: Alan Stern Signed-off-by: Andrey Konovalov Link: https://lore.kernel.org/r/a8d2b91f9890dc21daa359183e84879ff4525180.1693237258.git.andreyknvl@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/legacy/inode.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c index ce9e31f3d26b..6b929defc2d2 100644 --- a/drivers/usb/gadget/legacy/inode.c +++ b/drivers/usb/gadget/legacy/inode.c @@ -31,6 +31,12 @@ #include #include +#include /* for USB_GADGET_DELAYED_STATUS */ + +/* Undef helpers from linux/usb/composite.h as gadgetfs redefines them */ +#undef DBG +#undef ERROR +#undef INFO /* @@ -1511,7 +1517,16 @@ delegate: event->u.setup = *ctrl; ep0_readable (dev); spin_unlock (&dev->lock); - return 0; + /* + * Return USB_GADGET_DELAYED_STATUS as a workaround to + * stop some UDC drivers (e.g. dwc3) from automatically + * proceeding with the status stage for 0-length + * transfers. + * Should be removed once all UDC drivers are fixed to + * always delay the status stage until a response is + * queued to EP0. + */ + return w_length == 0 ? USB_GADGET_DELAYED_STATUS : 0; } } -- cgit