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From: Qiang Liu <cyruscyliu@gmail.com>
To: qemu-devel@nongnu.org
Cc: Gerd Hoffmann <kraxel@redhat.com>
Subject: [PATCH] hcd-ohci: Fix inconsistency when resetting ohci root hubs
Date: Tue, 30 Aug 2022 11:30:22 +0800	[thread overview]
Message-ID: <20220830033022.1164961-1-cyruscyliu@gmail.com> (raw)

I found an assertion failure in usb_cancel_packet() and posted my analysis in
https://gitlab.com/qemu-project/qemu/-/issues/1180. I think this issue is
because the inconsistency when resetting ohci root hubs.

There are two ways to reset ohci root hubs: 1) through HcRhPortStatus, 2)
through HcControl. However, when the packet's status is USB_PACKET_ASYNC,
resetting through HcRhPortStatus will complete the packet and thus resetting
through HcControl will fail. That is because IMO resetting through
HcRhPortStatus should first detach the port and then invoked usb_device_reset()
just like through HcControl. Therefore, I change usb_device_reset() to
usb_port_reset() where usb_detach() and usb_device_reset() are invoked
consequently.

Fixes: d28f4e2d8631 ("usb: kill USB_MSG_RESET")
Reported-by: Qiang Liu <cyruscyliu@gmail.com>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1180
Signed-off-by: Qiang Liu <cyruscyliu@gmail.com>
---
 hw/usb/hcd-ohci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c
index 895b29fb86..72df917834 100644
--- a/hw/usb/hcd-ohci.c
+++ b/hw/usb/hcd-ohci.c
@@ -1426,7 +1426,7 @@ static void ohci_port_set_status(OHCIState *ohci, int portnum, uint32_t val)
 
     if (ohci_port_set_if_connected(ohci, portnum, val & OHCI_PORT_PRS)) {
         trace_usb_ohci_port_reset(portnum);
-        usb_device_reset(port->port.dev);
+        usb_port_reset(&port->port);
         port->ctrl &= ~OHCI_PORT_PRS;
         /* ??? Should this also set OHCI_PORT_PESC.  */
         port->ctrl |= OHCI_PORT_PES | OHCI_PORT_PRSC;
-- 
2.25.1



             reply	other threads:[~2022-08-30  3:32 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-30  3:30 Qiang Liu [this message]
2024-04-08  9:17 ` [PATCH] hcd-ohci: Fix inconsistency when resetting ohci root hubs Philippe Mathieu-Daudé

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