Re: [PATCH v3 01/17] hw/usb/hcd-ehci: Remove unused EHCIfstn structure and dead code

[BALATON Zoltan <balaton@eik.bme.hu>]

On Thu, 16 Apr 2026, Jamin Lin wrote:
> The EHCIfstn structure, defined according to EHCI spec section 3.7,
> is currently unused in the EHCI implementation. Remove it to reduce
> unused code and improve maintainability.
>
> Additionally, drop a block of disabled (#if 0) code in
> ehci_state_advqueue() that was never implemented. This code path
> is incomplete and has no functional impact.
>
> No functional change.
>
> Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
> ---
> hw/usb/hcd-ehci.h |  7 -------
> hw/usb/hcd-ehci.c | 11 -----------
> 2 files changed, 18 deletions(-)
>
> diff --git a/hw/usb/hcd-ehci.h b/hw/usb/hcd-ehci.h
> index 0ae8c06331..3aec0e047c 100644
> --- a/hw/usb/hcd-ehci.h
> +++ b/hw/usb/hcd-ehci.h
> @@ -202,13 +202,6 @@ typedef struct EHCIqh {
> #define BUFPTR_SBYTES_SH              5
> } EHCIqh;
> 
> -/*  EHCI spec version 1.0 Section 3.7
> - */
> -typedef struct EHCIfstn {
> -    uint32_t next;                    /* Standard next link pointer */
> -    uint32_t backptr;                 /* Standard next link pointer */
> -} EHCIfstn;
> -
> enum async_state {
>     EHCI_ASYNC_NONE = 0,
>     EHCI_ASYNC_INITIALIZED,
> diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
> index 57f930b099..5ea8461f70 100644
> --- a/hw/usb/hcd-ehci.c
> +++ b/hw/usb/hcd-ehci.c
> @@ -1756,17 +1756,6 @@ static int ehci_state_fetchsitd(EHCIState *ehci, int async)
> /* Section 4.10.2 - paragraph 3 */
> static int ehci_state_advqueue(EHCIQueue *q)
> {
> -#if 0
> -    /* TO-DO: 4.10.2 - paragraph 2
> -     * if I-bit is set to 1 and QH is not active
> -     * go to horizontal QH
> -     */

Is it worth to keep the comment in case it's still valid to remind we have 
something missing here?

Regards,
BALATON Zoltan

> -    if (I-bit set) {
> -        ehci_set_state(ehci, async, EST_HORIZONTALQH);
> -        goto out;
> -    }
> -#endif
> -
>     /*
>      * want data and alt-next qTD is valid
>      */
> -- 
> 2.43.0
>