Am 12.04.2011 17:03, schrieb Amit Shah:
> On (Tue) 12 Apr 2011 [16:54:53], Kevin Wolf wrote:
>> Am 12.04.2011 16:09, schrieb Amit Shah:
>>> Implement the 'media' sub-command of the GET_EVENT_STATUS_NOTIFICATION
>>> command. This helps us report tray open, tray closed, no media, media
>>> present states to the guest.
>>>
>>> Newer Linux kernels (2.6.38+) rely on this command to revalidate discs
>>> after media change.
>>>
>>> This patch also sends out tray open/closed status to the guest driver
>>> when requested e.g. via the CDROM_DRIVE_STATUS ioctl (thanks Markus).
>>> Without such notification, the guest and qemu's tray open/close status
>>> was frequently out of sync, causing installers like Anaconda detecting
>>> no disc instead of tray open, confusing them terribly.
>>>
>>> Signed-off-by: Amit Shah <amit.s...@redhat.com>
>>> ---
>>> hw/ide/core.c | 109
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++--
>>> hw/ide/internal.h | 6 +++
>>> 2 files changed, 110 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/hw/ide/core.c b/hw/ide/core.c
>>> index dafc049..209d8e6 100644
>>> --- a/hw/ide/core.c
>>> +++ b/hw/ide/core.c
>>> @@ -1084,6 +1084,49 @@ static int ide_dvd_read_structure(IDEState *s, int
>>> format,
>>> }
>>> }
>>>
>>> +static unsigned int event_status_media(IDEState *s,
>>> + uint8_t *buf,
>>> + unsigned int max_len)
>>> +{
>>> + enum media_event_code {
>>> + no_change = 0, /* Status unchanged */
>>> + eject_requested, /* received a request from user to eject */
>>> + new_media, /* new media inserted and ready for access */
>>> + media_removal, /* only for media changers */
>>> + media_changed, /* only for media changers */
>>> + bg_format_completed, /* MRW or DVD+RW b/g format completed */
>>> + bg_format_restarted, /* MRW or DVD+RW b/g format restarted */
>>> + };
>>> + enum media_status {
>>> + tray_open = 1,
>>> + media_present = 2,
>>> + };
>>> + uint8_t event_code, media_status;
>>> +
>>> + media_status = 0;
>>> + if (s->bs->tray_open) {
>>> + media_status = tray_open;
>>> + } else if (bdrv_is_inserted(s->bs)) {
>>> + media_status = media_present;
>>> + }
>>> +
>>> + /* Event notification descriptor */
>>> + event_code = no_change;
>>> + if (media_status != tray_open && s->events.new_media) {
>>> + event_code = new_media;
>>> + s->events.new_media = false;
>>> + }
>>> +
>>> + buf[4] = event_code;
>>> + buf[5] = media_status;
>>> +
>>> + /* These fields are reserved, just clear them. */
>>> + buf[6] = 0;
>>> + buf[7] = 0;
>>> +
>>> + return 8; /* We wrote to 4 extra bytes from the header */
>>> +}
>>> +
>>> static void handle_get_event_status_notification(IDEState *s,
>>> uint8_t *buf,
>>> const uint8_t *packet)
>>> @@ -1104,6 +1147,26 @@ static void
>>> handle_get_event_status_notification(IDEState *s,
>>> uint8_t supported_events;
>>> } __attribute((packed)) *gesn_event_header;
>>>
>>> + enum notification_class_request_type {
>>> + reserved1 = 1 << 0,
>>> + operational_change = 1 << 1,
>>> + power_management = 1 << 2,
>>> + external_request = 1 << 3,
>>> + media = 1 << 4,
>>> + multi_host = 1 << 5,
>>> + device_busy = 1 << 6,
>>> + reserved2 = 1 << 7,
>>> + };
>>> + enum event_notification_class_field {
>>> + enc_no_events = 0,
>>> + enc_operational_change,
>>> + enc_power_management,
>>> + enc_external_request,
>>> + enc_media,
>>> + enc_multiple_hosts,
>>> + enc_device_busy,
>>> + enc_reserved,
>>> + };
>>> unsigned int max_len, used_len;
>>>
>>> gesn_cdb = (void *)packet;
>>> @@ -1121,12 +1184,25 @@ static void
>>> handle_get_event_status_notification(IDEState *s,
>>>
>>> /* polling mode operation */
>>>
>>> - /* We don't support any event class (yet). */
>>> - gesn_event_header->supported_events = 0;
>>> -
>>> - gesn_event_header->notification_class = 0x80; /* No event available */
>>> - used_len = sizeof(*gesn_event_header);
>>> + /*
>>> + * These are the supported events.
>>> + *
>>> + * We currently only support requests of the 'media' type.
>>> + */
>>> + gesn_event_header->supported_events = media;
>>>
>>> + /*
>>> + * Responses to requests are to be based on request priority. The
>>> + * notification_class_request_type enum above specifies the
>>> + * priority: upper elements are higher prio than lower ones.
>>> + */
>>> + if (gesn_cdb->class & media) {
>>> + gesn_event_header->notification_class |= enc_media;
>>
>> Am I missing where this field is initialized or should it be = instead
>> of |= ?
>
> I considered both: if the 'reserved' bits become available and if we
> should write to them, |= makes more sense. Currently, = will
> suffice. Strong preference?
|= is fine if the field is initialized to 0 and you add flags to it. But
this patch seems to remove the zero initialization. Maybe it's still
there somewhere, I just don't see it right now.
Kevin
