Re: [PATCHv13 4/7] fbmon: add videomode helpers

On Fri, Nov 23, 2012 at 12:52:08AM +0100, Laurent Pinchart wrote:

On Friday 23 November 2012 00:09:49 Steffen Trumtrar wrote:

quoted

On Thu, Nov 22, 2012 at 07:31:39PM +0100, Laurent Pinchart wrote:

quoted

On Thursday 22 November 2012 17:00:12 Steffen Trumtrar wrote:

quoted

Add a function to convert from the generic videomode to a fb_videomode.

Signed-off-by: Steffen Trumtrar <redacted>
Reviewed-by: Thierry Reding <redacted>
Acked-by: Thierry Reding <redacted>
Tested-by: Thierry Reding <redacted>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Steffen Trumtrar <redacted>
---

 drivers/video/fbmon.c |   44 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/fb.h    |    6 ++++++
 2 files changed, 50 insertions(+)

diff --git a/drivers/video/fbmon.c b/drivers/video/fbmon.c
index cef6557..a6a564d 100644
--- a/drivers/video/fbmon.c
+++ b/drivers/video/fbmon.c

@@ -31,6 +31,7 @@

 #include <linux/pci.h>
 #include <linux/slab.h>
 #include <video/edid.h>

+#include <linux/videomode.h>

 #ifdef CONFIG_PPC_OF
 #include <asm/prom.h>
 #include <asm/pci-bridge.h>

@@ -1373,6 +1374,49 @@ int fb_get_mode(int flags, u32 val, struct

fb_var_screeninfo *var, struct fb_inf kfree(timings);

 	return err;
 
 }

+
+#if IS_ENABLED(CONFIG_VIDEOMODE)
+int fb_videomode_from_videomode(const struct videomode *vm,
+				struct fb_videomode *fbmode)
+{
+	unsigned int htotal, vtotal;
+
+	fbmode->xres = vm->hactive;
+	fbmode->left_margin = vm->hback_porch;
+	fbmode->right_margin = vm->hfront_porch;
+	fbmode->hsync_len = vm->hsync_len;
+
+	fbmode->yres = vm->vactive;
+	fbmode->upper_margin = vm->vback_porch;
+	fbmode->lower_margin = vm->vfront_porch;
+	fbmode->vsync_len = vm->vsync_len;
+
+	fbmode->pixclock = KHZ2PICOS(vm->pixelclock / 1000);

This results in a division by 0 if vm->pixelclock is equal to zero. As the
information is missing from many board files, what would you think about
the following ?

	fbmode->pixclock = vm->pixelclock ? KHZ2PICOS(vm->pixelclock / 1000) : 0;

Grrr...you are right. I will fix that...

Thank you.

I have to thank you for bulletproofing my code o/\o

quoted

quoted

quoted

+	htotal = vm->hactive + vm->hfront_porch + vm->hback_porch +
+		 vm->hsync_len;
+	vtotal = vm->vactive + vm->vfront_porch + vm->vback_porch +
+		 vm->vsync_len;
+	fbmode->refresh = vm->pixelclock / (htotal * vtotal);
+

...and obviously this, too.

That one is less of an issue in my opinion. A mode with a zero htotal or 
vtotal is clearly invalid, while we have modes with no pixel clock value.

Yes, you I are right. But while I'm on it, might as well prevent an error.

Regards,
Steffen
-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |