[kernel/f16] Fix DVB-S2 to DVB-S switch back on Kaffeine

[mchehab]

commit 185d60abac1ba85ca761e3bbfe2f4d8c54f1ddc3
Author: Mauro Carvalho Chehab <mchehab at redhat.com>
Date:   Tue Apr 17 18:44:38 2012 -0300

    Fix DVB-S2 to DVB-S switch back on Kaffeine
    
    Kaffeine basically tried to switch back to DVB-S using FE_SET_FRONTEND.
    This ioctl was not designed to allow mode switching.
    
    The only ioctl that (explicitly) sets a mode is FE_SET_PROPERTY.
    
    Yet, there's a compat code there that should have been converting the
    call into something different than SYS_UNKNOWN.
    
    So, let's fix the code there. It will hopefully do the right thing.
    
    Signed-off-by: Mauro Carvalho Chehab <mchehab at redhat.com>

 dvb_frontend_switch_regression_fix.patch |   65 ++++++++++++++++++++++++++++++
 kernel.spec                              |    5 ++
 2 files changed, 70 insertions(+), 0 deletions(-)
---
diff --git a/dvb_frontend_switch_regression_fix.patch b/dvb_frontend_switch_regression_fix.patch
new file mode 100644
index 0000000..f5c7010
--- /dev/null
+++ b/dvb_frontend_switch_regression_fix.patch
@@ -0,0 +1,65 @@
+From c6c6fa8dcc27aad6ce3467544be0f57fd82b99a3 Mon Sep 17 00:00:00 2001
+From: Mauro Carvalho Chehab <mchehab at redhat.com>
+Date: Tue, 17 Apr 2012 18:32:19 -0300
+Subject: [PATCH] [media] dvb_frontend: Fix a regression when switching back
+ to DVB-S
+
+There are some softwares (Kaffeine and likely xine) that uses a
+DVBv5 call to switch to DVB-S2, but expects that a DVBv3 call to
+switch back to DVB-S. Well, this is not right, as a DVBv3 call
+doesn't know anything about delivery systems.
+
+However, as, by accident, this used to work, we need to restore its
+behavior, in order to avoid regressions with those softwares.
+
+Reported on this Fedora 16 bugzilla:
+	https://bugzilla.redhat.com/show_bug.cgi?id=812895
+
+Reported-by: Dieter Roever <Dieter.Roever at gmx.de>
+Signed-off-by: Mauro Carvalho Chehab <mchehab at redhat.com>
+
+diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c b/drivers/media/dvb/dvb-core/dvb_frontend.c
+index 4555baa..bb582fd 100644
+--- a/drivers/media/dvb/dvb-core/dvb_frontend.c
++++ b/drivers/media/dvb/dvb-core/dvb_frontend.c
+@@ -1443,6 +1443,28 @@ static int set_delivery_system(struct dvb_frontend *fe, u32 desired_system)
+ 				__func__);
+ 			return -EINVAL;
+ 		}
++		/*
++		 * Get a delivery system that is compatible with DVBv3
++		 * NOTE: in order for this to work with softwares like Kaffeine that
++		 *	uses a DVBv5 call for DVB-S2 and a DVBv3 call to go back to
++		 *	DVB-S, drivers that support both should put the SYS_DVBS entry
++		 *	before the SYS_DVBS2, otherwise it won't switch back to DVB-S.
++		 *	The real fix is that userspace applications should not use DVBv3
++		 *	and not trust on calling FE_SET_FRONTEND to switch the delivery
++		 *	system.
++		 */
++		ncaps = 0;
++		while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
++			if (fe->ops.delsys[ncaps] == desired_system) {
++				delsys = desired_system;
++				break;
++			}
++			ncaps++;
++		}
++		if (delsys == SYS_UNDEFINED) {
++			dprintk("%s() Couldn't find a delivery system that matches %d\n",
++				__func__, desired_system);
++		}
+ 	} else {
+ 		/*
+ 		 * This is a DVBv5 call. So, it likely knows the supported
+@@ -1491,9 +1513,10 @@ static int set_delivery_system(struct dvb_frontend *fe, u32 desired_system)
+ 				__func__);
+ 			return -EINVAL;
+ 		}
+-		c->delivery_system = delsys;
+ 	}
+ 
++	c->delivery_system = delsys;
++
+ 	/*
+ 	 * The DVBv3 or DVBv5 call is requesting a different system. So,
+ 	 * emulation is needed.
diff --git a/kernel.spec b/kernel.spec
index 423f3ba..2ce9ce0 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -710,6 +710,7 @@ Patch2802: linux-2.6-silence-acpi-blacklist.patch
 #   add-poll-requested-events.patch was added for 3.4
 Patch2900: add-poll-requested-events.patch
 Patch2901: drivers-media-update.patch
+Patch2902: dvb_frontend_switch_regression_fix.patch
 
 # fs fixes
 
@@ -1417,6 +1418,7 @@ ApplyPatch quite-apm.patch
 #  apply if non-empty
 ApplyPatch add-poll-requested-events.patch
 ApplyOptionalPatch drivers-media-update.patch
+ApplyPatch dvb_frontend_switch_regression_fix.patch
 
 # Patches headed upstream
 
@@ -2229,6 +2231,9 @@ fi
 # and build.
 
 %changelog
+* Tue Apr 17 2012 Mauro Carvalho Chehab <mchehab at redhat.com>
+- Fix DVB-S2->DVB-S switch regression (rhbz 812895)
+
 * Tue Apr 17 2012 Josh Boyer <jwboyer at redhat.com>
 - Fix oops in nfs_have_delegation (rhbz 811138)
 - Fix oops on invalid AMD microcode load (rhbz 797559)