Isaac Christensen (isaac.christensen@se-eng.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/6617
-gerrit
commit 158a6db183cbe33d301a94193082a0e2f751ee68 Author: Julius Werner jwerner@chromium.org Date: Tue Sep 3 16:44:15 2013 -0700
libpayload: usbhub: Don't clear PSC unless it was set
The current USB hub code always clears the port status change after checking it, regardless of whether it was set in the first place. Since this check runs on every poll, it might create a race condition where the port status changes right between the GET_PORT_STATUS and the CLEAR_FEATURE(C_PORT_CONNECT), thus clearing the statrus change flag before it was ever read. Let's add one extra if() to avoid that possible headache.
Change-Id: Idd46c2199dc6c240bd9ef068fbe70cccc88bac42 Signed-off-by: Julius Werner jwerner@chromium.org Reviewed-on: https://chromium-review.googlesource.com/168098 (cherry picked from commit f7f6f008f701ab3e4a4f785032d8024d676e11cb) Signed-off-by: Isaac Christensen isaac.christensen@se-eng.com --- payloads/libpayload/drivers/usb/usbhub.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/payloads/libpayload/drivers/usb/usbhub.c b/payloads/libpayload/drivers/usb/usbhub.c index 4e077f6..ff7904c 100644 --- a/payloads/libpayload/drivers/usb/usbhub.c +++ b/payloads/libpayload/drivers/usb/usbhub.c @@ -48,7 +48,8 @@ usb_hub_port_status_changed(usbdev_t *const dev, const int port) { unsigned short buf[2] = { 0, 0 }; get_status (dev, port, DR_PORT, 4, buf); - clear_feature (dev, port, SEL_C_PORT_CONNECTION, DR_PORT); + if (buf[1] & PORT_CONNECTION) + clear_feature (dev, port, SEL_C_PORT_CONNECTION, DR_PORT); return buf[1] & PORT_CONNECTION; }