[Qemu-devel] [PATCH 2.6 candidate] usb/uhci: move pid check

[Qemu-devel] [PATCH 2.6 candidate] usb/uhci: move pid check

[Gerd Hoffmann]

commit "5f77e06 usb: add pid check at the first of uhci_handle_td()"
moved the pid verification to the start of the uhci_handle_td function,
to simplify the error handling (we don't have to free stuff which we
didn't allocate in the first place ...).

Problem is now the check fires too often, it raises error IRQs even for
TDs which we are not going to process because they are not set active.

So, lets move down the check a bit, so it is done only for active TDs,
but still before we are going to allocate stuff to process the requested
transfer.

Reported-by: Joe Clifford <joe@thunderbug.co.uk>
Tested-by: Joe Clifford <joe@thunderbug.co.uk>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/usb/hcd-uhci.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/hw/usb/hcd-uhci.c b/hw/usb/hcd-uhci.c
index 18057bf..ca72a80 100644
--- a/hw/usb/hcd-uhci.c
+++ b/hw/usb/hcd-uhci.c
@@ -776,19 +776,6 @@ static int uhci_handle_td(UHCIState *s, UHCIQueue *q, uint32_t qh_addr,
     uint8_t pid = td->token & 0xff;
     UHCIAsync *async;
 
-    switch (pid) {
-    case USB_TOKEN_OUT:
-    case USB_TOKEN_SETUP:
-    case USB_TOKEN_IN:
-        break;
-    default:
-        /* invalid pid : frame interrupted */
-        s->status |= UHCI_STS_HCPERR;
-        s->cmd &= ~UHCI_CMD_RS;
-        uhci_update_irq(s);
-        return TD_RESULT_STOP_FRAME;
-    }
-
     async = uhci_async_find_td(s, td_addr);
     if (async) {
         if (uhci_queue_verify(async->queue, qh_addr, td, td_addr, queuing)) {
@@ -828,6 +815,19 @@ static int uhci_handle_td(UHCIState *s, UHCIQueue *q, uint32_t qh_addr,
         return TD_RESULT_NEXT_QH;
     }
 
+    switch (pid) {
+    case USB_TOKEN_OUT:
+    case USB_TOKEN_SETUP:
+    case USB_TOKEN_IN:
+        break;
+    default:
+        /* invalid pid : frame interrupted */
+        s->status |= UHCI_STS_HCPERR;
+        s->cmd &= ~UHCI_CMD_RS;
+        uhci_update_irq(s);
+        return TD_RESULT_STOP_FRAME;
+    }
+
     if (async) {
         if (queuing) {
             /* we are busy filling the queue, we are not prepared
-- 
1.8.3.1

Re: [Qemu-devel] [PATCH 2.6 candidate] usb/uhci: move pid check

[Peter Maydell]

On 22 April 2016 at 11:44, Gerd Hoffmann <kraxel@redhat.com> wrote:
> commit "5f77e06 usb: add pid check at the first of uhci_handle_td()"
> moved the pid verification to the start of the uhci_handle_td function,
> to simplify the error handling (we don't have to free stuff which we
> didn't allocate in the first place ...).
>
> Problem is now the check fires too often, it raises error IRQs even for
> TDs which we are not going to process because they are not set active.
>
> So, lets move down the check a bit, so it is done only for active TDs,
> but still before we are going to allocate stuff to process the requested
> transfer.
>
> Reported-by: Joe Clifford <joe@thunderbug.co.uk>
> Tested-by: Joe Clifford <joe@thunderbug.co.uk>
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

Applied to master, thanks.

-- PMM