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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Jack Pham <jackp@codeaurora.org>,
	Ronak Vijay Raheja <rraheja@codeaurora.org>,
	Felipe Balbi <balbi@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Sasha Levin <sashal@kernel.org>,
	linux-usb@vger.kernel.org
Subject: [PATCH AUTOSEL 5.4 020/109] usb: gadget: composite: Allow bMaxPower=0 if self-powered
Date: Thu,  9 Sep 2021 07:53:37 -0400	[thread overview]
Message-ID: <20210909115507.147917-20-sashal@kernel.org> (raw)
In-Reply-To: <20210909115507.147917-1-sashal@kernel.org>

From: Jack Pham <jackp@codeaurora.org>

[ Upstream commit bcacbf06c891374e7fdd7b72d11cda03b0269b43 ]

Currently the composite driver encodes the MaxPower field of
the configuration descriptor by reading the c->MaxPower of the
usb_configuration only if it is non-zero, otherwise it falls back
to using the value hard-coded in CONFIG_USB_GADGET_VBUS_DRAW.
However, there are cases when a configuration must explicitly set
bMaxPower to 0, particularly if its bmAttributes also has the
Self-Powered bit set, which is a valid combination.

This is specifically called out in the USB PD specification section
9.1, in which a PDUSB device "shall report zero in the bMaxPower
field after negotiating a mutually agreeable Contract", and also
verified by the USB Type-C Functional Test TD.4.10.2 Sink Power
Precedence Test.

The fix allows the c->MaxPower to be used for encoding the bMaxPower
even if it is 0, if the self-powered bit is also set.  An example
usage of this would be for a ConfigFS gadget to be dynamically
updated by userspace when the Type-C connection is determined to be
operating in Power Delivery mode.

Co-developed-by: Ronak Vijay Raheja <rraheja@codeaurora.org>
Acked-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Ronak Vijay Raheja <rraheja@codeaurora.org>
Signed-off-by: Jack Pham <jackp@codeaurora.org>
Link: https://lore.kernel.org/r/20210720080907.30292-1-jackp@codeaurora.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/gadget/composite.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 24dad1d78d1e..6bd3fdb925cd 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -481,7 +481,7 @@ static u8 encode_bMaxPower(enum usb_device_speed speed,
 {
 	unsigned val;
 
-	if (c->MaxPower)
+	if (c->MaxPower || (c->bmAttributes & USB_CONFIG_ATT_SELFPOWER))
 		val = c->MaxPower;
 	else
 		val = CONFIG_USB_GADGET_VBUS_DRAW;
@@ -905,7 +905,11 @@ static int set_config(struct usb_composite_dev *cdev,
 	}
 
 	/* when we return, be sure our power usage is valid */
-	power = c->MaxPower ? c->MaxPower : CONFIG_USB_GADGET_VBUS_DRAW;
+	if (c->MaxPower || (c->bmAttributes & USB_CONFIG_ATT_SELFPOWER))
+		power = c->MaxPower;
+	else
+		power = CONFIG_USB_GADGET_VBUS_DRAW;
+
 	if (gadget->speed < USB_SPEED_SUPER)
 		power = min(power, 500U);
 	else
-- 
2.30.2


  parent reply	other threads:[~2021-09-09 12:47 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20210909115507.147917-1-sashal@kernel.org>
2021-09-09 11:53 ` [PATCH AUTOSEL 5.4 016/109] usb: host: fotg210: fix the endpoint's transactional opportunities calculation Sasha Levin
2021-09-09 11:53 ` [PATCH AUTOSEL 5.4 017/109] usb: host: fotg210: fix the actual_length of an iso packet Sasha Levin
2021-09-09 11:53 ` [PATCH AUTOSEL 5.4 018/109] usb: gadget: u_ether: fix a potential null pointer dereference Sasha Levin
2021-09-09 11:53 ` [PATCH AUTOSEL 5.4 019/109] USB: EHCI: ehci-mv: improve error handling in mv_ehci_enable() Sasha Levin
2021-09-09 11:53 ` Sasha Levin [this message]
2021-09-09 11:54 ` [PATCH AUTOSEL 5.4 077/109] usb: chipidea: host: fix port index underflow and UBSAN complains Sasha Levin
2021-09-09 11:54 ` [PATCH AUTOSEL 5.4 093/109] Revert "USB: xhci: fix U1/U2 handling for hardware with XHCI_INTEL_HOST quirk set" Sasha Levin
2021-09-09 11:54 ` [PATCH AUTOSEL 5.4 094/109] usb: musb: musb_dsps: request_irq() after initializing musb Sasha Levin
2021-09-09 11:54 ` [PATCH AUTOSEL 5.4 095/109] usbip: give back URBs for unsent unlink requests during cleanup Sasha Levin
2021-09-09 11:54 ` [PATCH AUTOSEL 5.4 096/109] usbip:vhci_hcd USB port can get stuck in the disabled state Sasha Levin

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