HDMI 800x480 resolution in Yocto Pyro

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HDMI 800x480 resolution in Yocto Pyro

Postby eiger824 » Mon Oct 23, 2017 6:15 pm

Hey there!

I am struggling to set the correct resolution to an HDMI 5' 800x480 touchscreen that I recently bought (https://www.adafruit.com/product/2260). I am using a Wandboard Dual Rev. D1.

I am aware that a command line argument must be passed on to the kernel to set the video mode, in my case I provide the following in my local.conf file:

Code: Select all
# Set the video mode
UBOOT_EXTLINUX_KERNEL_ARGS_append = " video=mxcfb0:dev=hdmi,800x480M@60,if=RGB24"


The problem is that I am getting a lot of disturbances in the screen, it seems that I am not feeding exactly 800x480 to the screen.

Anybody who has experienced the same problem using an HDMI display with this resolution?

I also tested adding two new entries with the modes I want (i.e. 800x480@60 with two aspect rates) in the
Code: Select all
mxc_cea_mode
array in drivers/video/fbdev/mxc/mxc_edid.c, and patching it so it is included on my builds. This is the patched file:
Code: Select all
From ec8f562546948469e10d29a627edcfb337c33f8d Mon Sep 17 00:00:00 2001
From: Santi Pagola <santipagola@gmail.com>
Date: Mon, 23 Oct 2017 19:13:40 +0200
Subject: [PATCH] Add custom resolution to fb modes

---
 drivers/video/fbdev/mxc/mxc_edid.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/video/fbdev/mxc/mxc_edid.c b/drivers/video/fbdev/mxc/mxc_edid.c
index 23110ce..7968291 100644
--- a/drivers/video/fbdev/mxc/mxc_edid.c
+++ b/drivers/video/fbdev/mxc/mxc_edid.c
@@ -180,6 +180,16 @@ const struct fb_videomode mxc_cea_mode[64] = {
       FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
       FB_VMODE_NONINTERLACED | FB_VMODE_ASPECT_16_9, 0
    },
+   /* #48: 800x480p@59.94/60Hz 4:3 */
+   [48] = {
+      NULL, 60, 800, 480, 37037, 60, 16, 30, 9, 62, 6, 0,
+      FB_VMODE_NONINTERLACED | FB_VMODE_ASPECT_4_3, 0,
+   },
+   /* #49: 800x480p@59.94/60Hz 16:9 */
+   [49] = {
+      NULL, 60, 800, 480, 37037, 60, 16, 30, 9, 62, 6, 0,
+      FB_VMODE_NONINTERLACED | FB_VMODE_ASPECT_16_9, 0,
+   },
 };
 
 /*
--
2.7.4


Any ideas?

Thank you in advance!
/eiger824
eiger824
 
Posts: 10
Joined: Tue Jun 13, 2017 8:18 am

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