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https://github.com/edk2-porting/linux-next.git
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a899575191
This patch fixes a race condition that caused the HWA_HC interface probe function to occasionally fail. The HWA_HC would attempt to register itself with the HWA_RC by searching for a uwb_rc class device with the same parent device ptr. If the probe function for the HWA_RC interface had yet to run, the uwb_rc class device would not have been created causing the look up to fail and the HWA_HC probe function to return an error causing the device to be unusable. The fix is for the HWA to delay registering with the HWA_RC until receiving the command from userspace to start the wireless channel. It is the responsibility of userspace to ensure that the uwb_rc class device has been created before starting the HWA channel. Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
56 lines
1.5 KiB
C
56 lines
1.5 KiB
C
/*
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* Wireless USB Host Controller
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* UWB Protocol Adaptation Layer (PAL) glue.
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*
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* Copyright (C) 2008 Cambridge Silicon Radio Ltd.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version
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* 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "wusbhc.h"
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static void wusbhc_channel_changed(struct uwb_pal *pal, int channel)
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{
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struct wusbhc *wusbhc = container_of(pal, struct wusbhc, pal);
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if (channel < 0)
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wusbhc_stop(wusbhc);
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else
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wusbhc_start(wusbhc);
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}
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/**
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* wusbhc_pal_register - register the WUSB HC as a UWB PAL
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* @wusbhc: the WUSB HC
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*/
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int wusbhc_pal_register(struct wusbhc *wusbhc)
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{
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uwb_pal_init(&wusbhc->pal);
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wusbhc->pal.name = "wusbhc";
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wusbhc->pal.device = wusbhc->usb_hcd.self.controller;
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wusbhc->pal.rc = wusbhc->uwb_rc;
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wusbhc->pal.channel_changed = wusbhc_channel_changed;
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return uwb_pal_register(&wusbhc->pal);
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}
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/**
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* wusbhc_pal_unregister - unregister the WUSB HC as a UWB PAL
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* @wusbhc: the WUSB HC
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*/
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void wusbhc_pal_unregister(struct wusbhc *wusbhc)
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{
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if (wusbhc->uwb_rc)
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uwb_pal_unregister(&wusbhc->pal);
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}
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