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[Qemu-devel] Re: [PATCH 5/5] atapi: Implement 'media' subcommand of GET_
From: |
Amit Shah |
Subject: |
[Qemu-devel] Re: [PATCH 5/5] atapi: Implement 'media' subcommand of GET_EVENT_STATUS_NOTIFICATION command |
Date: |
Sat, 9 Apr 2011 19:27:32 +0530 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On (Fri) 08 Apr 2011 [18:17:38], Kevin Wolf wrote:
> Am 08.04.2011 09:15, 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 <address@hidden>
> > ---
> > hw/ide/core.c | 93
> > +++++++++++++++++++++++++++++++++++++++++++++++++++-
> > hw/ide/internal.h | 6 +++
> > 2 files changed, 97 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/ide/core.c b/hw/ide/core.c
> > index cdc2c56..627b2cf 100644
> > --- a/hw/ide/core.c
> > +++ b/hw/ide/core.c
> > @@ -1084,6 +1084,57 @@ 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,
> > + unsigned int event_class,
> > + unsigned int supported_events)
> > +{
> > + 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;
> > +
> > + if (max_len < 6) {
> > + /* We're going to use 6 bytes; don't report anything if we have
> > less */
> > + return 0;
> > + }
>
> Why? Shouldn't we report the first few bytes?
This shouldn't be necessary at all now, isn't it?
> > +
> > + /* Event notification header */
> > + cpu_to_ube16(buf, max_len);
> > + buf[2] = event_class;
> > + buf[3] = supported_events;
>
> This should be done in handle_get_event_status_notification as it's not
> specific for media events.
Yes, I moved it here just before the submission. With the used_len
stuff not being needed anymore, this can be put back there and code
won't look too ugly.
> > + 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;
> > +
> > + return 6; /* We wrote to just 2 extra bytes from the header */
>
> After media_state, there are two more fields for start/end slot (even
> though they are reserved because we don't have a multiple slot device)
Yes, they're reserved, so we shouldn't change them. Any change might
trigger bad response from guests.
> So I think we should return 8 and possible zero bytes 6 and 7.
>
> > +}
> > +
> > static unsigned int event_status_nea(uint8_t *buf, unsigned int max_len)
> > {
> > unsigned int used_len;
> > @@ -1125,7 +1176,28 @@ static void
> > handle_get_event_status_notification(IDEState *s,
> > allocation_length_lsb = 8,
> > control = 9,
> > };
> > + 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;
> > + unsigned int supported_events;
> >
> > max_len = ube16_to_cpu(packet + allocation_length_msb);
> >
> > @@ -1139,8 +1211,24 @@ static void
> > handle_get_event_status_notification(IDEState *s,
> >
> > /* polling mode operation */
> >
> > - /* We don't support any event class (yet). */
> > - used_len = event_status_nea(buf, max_len);
> > + /*
> > + * These are the supported events.
> > + *
> > + * We currently only support requests of the 'media' type.
> > + */
> > + 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 (packet[request] & media) {
> > + used_len = event_status_media(s, buf, max_len, enc_media,
> > + supported_events);
> > + } else {
> > + used_len = event_status_nea(buf, max_len);
> > + }
>
> Once you put the event header here, there's no need for event_status_nea
> any more because it just mean not adding any descriptors. That will work
> much better as soon as we have more even classes, too.
Hm, I didn't do it that way when I first coded this so there must've
been something that I'm forgetting now.
>
> > ide_atapi_cmd_reply(s, used_len, max_len);
> > }
> >
> > @@ -1661,6 +1749,7 @@ static void cdrom_change_cb(void *opaque, int reason)
> > s->sense_key = SENSE_UNIT_ATTENTION;
> > s->asc = ASC_MEDIUM_MAY_HAVE_CHANGED;
> > s->cdrom_changed = 1;
> > + s->events.new_media = true;
> > ide_set_irq(s->bus);
> > }
> >
> > diff --git a/hw/ide/internal.h b/hw/ide/internal.h
> > index d533fb6..ba7e9a8 100644
> > --- a/hw/ide/internal.h
> > +++ b/hw/ide/internal.h
> > @@ -373,6 +373,11 @@ typedef int DMAFunc(IDEDMA *);
> > typedef int DMAIntFunc(IDEDMA *, int);
> > typedef void DMARestartFunc(void *, int, int);
> >
> > +struct unreported_events {
> > + bool eject_request;
> > + bool new_media;
> > +};
> > +
> > /* NOTE: IDEState represents in fact one drive */
> > struct IDEState {
> > IDEBus *bus;
> > @@ -408,6 +413,7 @@ struct IDEState {
> > BlockDriverState *bs;
> > char version[9];
> > /* ATAPI specific */
> > + struct unreported_events events;
> > uint8_t sense_key;
> > uint8_t asc;
> > uint8_t cdrom_changed;
>
> Do we need to add some vmstate fields?
Yes! I had it in mind till sometime back.
Amit