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[3.19.y-ckt,064/160] video: fbdev: fsl: Fix kernel crash when diu_ops is not implemented

Message ID 1453252038-31915-65-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa Jan. 20, 2016, 1:05 a.m. UTC 
3.19.8-ckt13 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Wang Dongsheng <dongsheng.wang@freescale.com>

commit acfc1cc13fe5bc6d7a10afa624f1e560850ddad3 upstream.

If diu_ops is not implemented on platform, kernel will access a NULL
pointer. We need to check this pointer in DIU initialization.

Signed-off-by: Wang Dongsheng <dongsheng.wang@freescale.com>
Acked-by: Timur Tabi <timur@tabi.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/video/fbdev/fsl-diu-fb.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)
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Patch

diff --git a/drivers/video/fbdev/fsl-diu-fb.c b/drivers/video/fbdev/fsl-diu-fb.c
index 7fa2e6f..2a1fde6 100644
--- a/drivers/video/fbdev/fsl-diu-fb.c
+++ b/drivers/video/fbdev/fsl-diu-fb.c
@@ -479,7 +479,10 @@  static enum fsl_diu_monitor_port fsl_diu_name_to_port(const char *s)
 			port = FSL_DIU_PORT_DLVDS;
 	}
 
-	return diu_ops.valid_monitor_port(port);
+	if (diu_ops.valid_monitor_port)
+		port = diu_ops.valid_monitor_port(port);
+
+	return port;
 }
 
 /*
@@ -1908,6 +1911,14 @@  static int __init fsl_diu_init(void)
 #else
 	monitor_port = fsl_diu_name_to_port(monitor_string);
 #endif
+
+	/*
+	 * Must to verify set_pixel_clock. If not implement on platform,
+	 * then that means that there is no platform support for the DIU.
+	 */
+	if (!diu_ops.set_pixel_clock)
+		return -ENODEV;
+
 	pr_info("Freescale Display Interface Unit (DIU) framebuffer driver\n");
 
 #ifdef CONFIG_NOT_COHERENT_CACHE