linux-kernel - [PATCH 4.12 078/196] [media] cx88: Fix regression in initial video standard setting

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Date:   Tue, 25 Jul 2017 12:21:17 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Devin Heitmueller <dheitmueller@...nellabs.com>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Mauro Carvalho Chehab <mchehab@...pensource.com>
Subject: [PATCH 4.12 078/196] [media] cx88: Fix regression in initial video standard setting

4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Devin Heitmueller <dheitmueller@...nellabs.com>

commit 4e0973a918b9a42e217093f078e04a61e5dd95a5 upstream.

Setting initial standard at the top of cx8800_initdev would cause the
first call to cx88_set_tvnorm() to return without programming any
registers (leaving the driver saying it's set to NTSC but the hardware
isn't programmed).  Even worse, any subsequent attempt to explicitly
set it to NTSC-M will return success but actually fail to program the
underlying registers unless first changing the standard to something
other than NTSC-M.

Set the initial standard later in the process, and make sure the field
is zero at the beginning to ensure that the call always goes through.

This regression was introduced in the following commit:

commit ccd6f1d488e7 ("[media] cx88: move width, height and field to core
struct")

Author: Hans Verkuil <hans.verkuil@...co.com>

[media] cx88: move width, height and field to core struct

Signed-off-by: Devin Heitmueller <dheitmueller@...nellabs.com>
Signed-off-by: Hans Verkuil <hans.verkuil@...co.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...pensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/media/pci/cx88/cx88-cards.c |    9 ++++++++-
 drivers/media/pci/cx88/cx88-video.c |    2 +-
 2 files changed, 9 insertions(+), 2 deletions(-)

--- a/drivers/media/pci/cx88/cx88-cards.c
+++ b/drivers/media/pci/cx88/cx88-cards.c
@@ -3681,7 +3681,14 @@ struct cx88_core *cx88_core_create(struc
 	core->nr = nr;
 	sprintf(core->name, "cx88[%d]", core->nr);
 
-	core->tvnorm = V4L2_STD_NTSC_M;
+	/*
+	 * Note: Setting initial standard here would cause first call to
+	 * cx88_set_tvnorm() to return without programming any registers.  Leave
+	 * it blank for at this point and it will get set later in
+	 * cx8800_initdev()
+	 */
+	core->tvnorm  = 0;
+
 	core->width   = 320;
 	core->height  = 240;
 	core->field   = V4L2_FIELD_INTERLACED;
--- a/drivers/media/pci/cx88/cx88-video.c
+++ b/drivers/media/pci/cx88/cx88-video.c
@@ -1435,7 +1435,7 @@ static int cx8800_initdev(struct pci_dev
 
 	/* initial device configuration */
 	mutex_lock(&core->lock);
-	cx88_set_tvnorm(core, core->tvnorm);
+	cx88_set_tvnorm(core, V4L2_STD_NTSC_M);
 	v4l2_ctrl_handler_setup(&core->video_hdl);
 	v4l2_ctrl_handler_setup(&core->audio_hdl);
 	cx88_video_mux(core, 0);