Re: [Qemu-devel] [PATCH v2] fdc: fix media change detection for windows

[Kevin Wolf <kwolf@redhat.com>]

Am 05.06.2012 17:50, schrieb Pavel Hrdina:
> Sorry, I forget the qtest. I'll create it and send it again.
> 
> Pavel
> 
> On 06/05/2012 05:46 PM, Pavel Hrdina wrote:
>> The Windows uses 'READ' command at the start of an instalation
>> without checking the 'dir' register. We have to abort the transfer
>> with an abnormal termination if there is no media in the drive.
>>
>> We have to also check the 'media_change' bit in the 'fd_seek'. This
>> internal seek clears the 'media_change' bit, too, if there is
>> a media inserted.
>>
>> Signed-off-by: Pavel Hrdina<phrdina@redhat.com>
>> ---
>>   hw/fdc.c |    7 ++++++-
>>   1 files changed, 6 insertions(+), 1 deletions(-)
>>
>> diff --git a/hw/fdc.c b/hw/fdc.c
>> index 30d34e3..2d6dd30 100644
>> --- a/hw/fdc.c
>> +++ b/hw/fdc.c
>> @@ -127,8 +127,13 @@ static int fd_seek(FDrive *drv, uint8_t head, uint8_t track, uint8_t sect,
>>       uint32_t sector;
>>       int ret;
>>
>> +    if (drv->bs != NULL&&  bdrv_is_inserted(drv->bs)) {
>> +        drv->media_changed = 0;
>> +    }
>> +
>>       if (track>  drv->max_track ||
>> -        (head != 0&&  (drv->flags&  FDISK_DBL_SIDES) == 0)) {
>> +        (head != 0&&  (drv->flags&  FDISK_DBL_SIDES) == 0) ||
>> +        drv->media_changed) {

Why not directly use bdrv_is_inserted() here?

Fiddling around with media_changed feels rather hacky and is strictly
speaking incorrect because a step pulse is not guaranteed to happen in
the following code. The floppy code doesn't get it quite right today
anyway, but a hack like this would contribute to the problem.


>>           FLOPPY_DPRINTF("try to read %d %02x %02x (max=%d %d %02x %02x)\n",
>>                          head, track, sect, 1,
>>                          (drv->flags&  FDISK_DBL_SIDES) == 0 ? 0 : 1,

Kevin