From: BALATON Zoltan <[email protected]>

According to the USB OHCI specification section 6.5.6
("FrameNumberOverflow Event"), when bit 15 of the frame count changes
(either from 1 to 0 or 0 to 1) a FrameNumberOverflow interrupt should
be generated.

This fixes usb-audio on mac99,via=pmu with MacOS 9.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3274
Signed-off-by: BALATON Zoltan <[email protected]>
Tested-by: Elisey Konstantinov <[email protected]>
Message-id: [email protected]
[PMM: added brief comment, tweaked commit message]
Signed-off-by: Peter Maydell <[email protected]>
Reviewed-by: Peter Maydell <[email protected]>
---
 hw/usb/hcd-ohci.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c
index c7e9c71903..1aeed9286f 100644
--- a/hw/usb/hcd-ohci.c
+++ b/hw/usb/hcd-ohci.c
@@ -1246,6 +1246,10 @@ static void ohci_frame_boundary(void *opaque)
     hcca.frame = cpu_to_le16(ohci->frame_number);
     /* When the HC updates frame number, set pad to 0. Ref OHCI Spec 4.4.1*/
     hcca.pad = 0;
+    /* FrameNumberOverflow happens when bit 15 of frame number changes */
+    if (ohci->frame_number == 0x8000 || ohci->frame_number == 0) {
+        ohci_set_interrupt(ohci, OHCI_INTR_FNO);
+    }
 
     if (ohci->done_count == 0 && !(ohci->intr_status & OHCI_INTR_WD)) {
         if (!ohci->done) {
-- 
2.43.0


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