Re: [Qemu-devel] [PATCH] ohci: don't die on ED_LINK_LIMIT overflow

[BALATON Zoltan]

On Thu, 21 Mar 2019, Laurent Vivier wrote:
> Stop processing the descriptor list instead. The next frame timer tick will
> resume the work

Shoud this log something when the limit is reached to let the user know 
why USB stopped working instead of silently ignoring frames?

Regards,
BALATON Zoltan

> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1686705
> Suggested-by: Gerd Hoffmann <address@hidden>
> Signed-off-by: Laurent Vivier <address@hidden>
> ---
> hw/usb/hcd-ohci.c | 7 +------
> 1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c
> index 196a9f72002d..81cf5ab7a5a7 100644
> --- a/hw/usb/hcd-ohci.c
> +++ b/hw/usb/hcd-ohci.c
> @@ -1200,7 +1200,7 @@ static int ohci_service_ed_list(OHCIState *ohci, uint32_t 
> head, int completion)
>     if (head == 0)
>         return 0;
>
> -    for (cur = head; cur; cur = next_ed) {
> +    for (cur = head; cur && link_cnt++ < ED_LINK_LIMIT; cur = next_ed) {
>         if (ohci_read_ed(ohci, cur, &ed)) {
>             trace_usb_ohci_ed_read_error(cur);
>             ohci_die(ohci);
> @@ -1209,11 +1209,6 @@ static int ohci_service_ed_list(OHCIState *ohci, 
> uint32_t head, int completion)
>
>         next_ed = ed.next & OHCI_DPTR_MASK;
>
> -        if (++link_cnt > ED_LINK_LIMIT) {
> -            ohci_die(ohci);
> -            return 0;
> -        }
> -
>         if ((ed.head & OHCI_ED_H) || (ed.flags & OHCI_ED_K)) {
>             uint32_t addr;
>             /* Cancel pending packets for ED that have been paused.  */