Re: [PATCH 2/4] hw/block/fdc: Remove the check_media_rate property

[John Snow]

On 2/3/21 12:18 PM, Thomas Huth wrote:
> This was only required for the pc-1.0 and earlier machine types.
> Now that these have been removed, we can also drop the corresponding
> code from the FDC device.
>
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>   hw/block/fdc.c             | 17 ++---------------
>   tests/qemu-iotests/172.out | 35 -----------------------------------
>   2 files changed, 2 insertions(+), 50 deletions(-)
>
> diff --git a/hw/block/fdc.c b/hw/block/fdc.c
> index 292ea87805..198940e737 100644
> --- a/hw/block/fdc.c
> +++ b/hw/block/fdc.c
> @@ -874,7 +874,6 @@ struct FDCtrl {
>           FloppyDriveType type;
>       } qdev_for_drives[MAX_FD];
>       int reset_sensei;
> -    uint32_t check_media_rate;

I am a bit of a dunce when it comes to the compatibility properties... 
does this mess with the migration format?

I guess it doesn't, since it's not in the VMSTATE declaration.

Hmmmm, alright.

>       FloppyDriveType fallback; /* type=auto failure fallback */
>       /* Timers state */
>       uint8_t timer0;
> @@ -1021,18 +1020,10 @@ static const VMStateDescription 
> vmstate_fdrive_media_changed = {
>       }
>   };
>   
> -static bool fdrive_media_rate_needed(void *opaque)
> -{
> -    FDrive *drive = opaque;
> -
> -    return drive->fdctrl->check_media_rate;
> -}
> -
>   static const VMStateDescription vmstate_fdrive_media_rate = {
>       .name = "fdrive/media_rate",
>       .version_id = 1,
>       .minimum_version_id = 1,
> -    .needed = fdrive_media_rate_needed,
>       .fields = (VMStateField[]) {
>           VMSTATE_UINT8(media_rate, FDrive),
>           VMSTATE_END_OF_LIST()
> @@ -1689,8 +1680,7 @@ static void fdctrl_start_transfer(FDCtrl *fdctrl, int 
> direction)
>   
>       /* Check the data rate. If the programmed data rate does not match
>        * the currently inserted medium, the operation has to fail. */
> -    if (fdctrl->check_media_rate &&
> -        (fdctrl->dsr & FD_DSR_DRATEMASK) != cur_drv->media_rate) {
> +    if ((fdctrl->dsr & FD_DSR_DRATEMASK) != cur_drv->media_rate) {
>           FLOPPY_DPRINTF("data rate mismatch (fdc=%d, media=%d)\n",
>                          fdctrl->dsr & FD_DSR_DRATEMASK, cur_drv->media_rate);
>           fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM, FD_SR1_MA, 0x00);
> @@ -2489,8 +2479,7 @@ static void fdctrl_result_timer(void *opaque)
>           cur_drv->sect = (cur_drv->sect % cur_drv->last_sect) + 1;
>       }
>       /* READ_ID can't automatically succeed! */
> -    if (fdctrl->check_media_rate &&
> -        (fdctrl->dsr & FD_DSR_DRATEMASK) != cur_drv->media_rate) {
> +    if ((fdctrl->dsr & FD_DSR_DRATEMASK) != cur_drv->media_rate) {
>           FLOPPY_DPRINTF("read id rate mismatch (fdc=%d, media=%d)\n",
>                          fdctrl->dsr & FD_DSR_DRATEMASK, cur_drv->media_rate);
>           fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM, FD_SR1_MA, 0x00);
> @@ -2895,8 +2884,6 @@ static Property isa_fdc_properties[] = {
>       DEFINE_PROP_UINT32("dma", FDCtrlISABus, dma, 2),
>       DEFINE_PROP_DRIVE("driveA", FDCtrlISABus, state.qdev_for_drives[0].blk),
>       DEFINE_PROP_DRIVE("driveB", FDCtrlISABus, state.qdev_for_drives[1].blk),
> -    DEFINE_PROP_BIT("check_media_rate", FDCtrlISABus, state.check_media_rate,
> -                    0, true),

Could you theoretically set this via QOM commands in QMP, and claim that 
this is a break in behavior?

Though, it's ENTIRELY undocumented, so ... it's probably fine, I think. 
Probably. (Please soothe my troubled mind.)

--js