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authorChris Rankin <rankincj@yahoo.com>2012-04-06 18:38:18 -0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-04-13 09:13:57 -0700
commit72043dfc657fa79898ec740fc7387b0efd767422 (patch)
parent4b06fc96136303af61cd835bb1504f50cb23a615 (diff)
media: dvb_frontend: regression fix: userspace ABI broken for xine
commit 556a0442e08a8bc8541587a349cbf26ed14ec6de upstream. The commit e399ce77e6e has broken the DVB ABI for xine: The problem is that xine is expecting every event after a successful FE_SET_FRONTEND ioctl to have a non-zero frequency parameter, regardless of whether the tuning process has LOCKed yet. What used to happen is that the events inherited the initial tuning parameters from the FE_SET_FRONTEND call. However, the fepriv->parameters_out struct is now not initialised until the status contains the FE_HAS_LOCK bit. You might argue that this behaviour is intentional, except that if an application other than xine uses the DVB adapter and manages to set the parameters_out.frequency field to something other than zero, then xine no longer has any problems until either the adapter is replugged or the kernel modules reloaded. This can only mean that the fepriv->parameters_out struct still contains the (stale) tuning information from the previous application. Signed-off-by: Chris Rankin <rankincj@yahoo.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c b/drivers/media/dvb/dvb-core/dvb_frontend.c
index fbbe545a74cb..eb376732cad5 100644
--- a/drivers/media/dvb/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb/dvb-core/dvb_frontend.c
@@ -143,6 +143,8 @@ struct dvb_frontend_private {
static void dvb_frontend_wakeup(struct dvb_frontend *fe);
static int dtv_get_frontend(struct dvb_frontend *fe,
struct dvb_frontend_parameters *p_out);
+static int dtv_property_legacy_params_sync(struct dvb_frontend *fe,
+ struct dvb_frontend_parameters *p);
static bool has_get_frontend(struct dvb_frontend *fe)
@@ -695,6 +697,7 @@ restart:
fepriv->algo_status |= DVBFE_ALGO_SEARCH_AGAIN;
fepriv->delay = HZ / 2;
+ dtv_property_legacy_params_sync(fe, &fepriv->parameters_out);
fe->ops.read_status(fe, &s);
if (s != fepriv->status) {
dvb_frontend_add_event(fe, s); /* update event list */
@@ -1831,6 +1834,13 @@ static int dtv_set_frontend(struct dvb_frontend *fe)
return -EINVAL;
+ * Initialize output parameters to match the values given by
+ * the user. FE_SET_FRONTEND triggers an initial frontend event
+ * with status = 0, which copies output parameters to userspace.
+ */
+ dtv_property_legacy_params_sync(fe, &fepriv->parameters_out);
+ /*
* Be sure that the bandwidth will be filled for all
* non-satellite systems, as tuners need to know what
* low pass/Nyquist half filter should be applied, in