Hello Laurent,
Thanks for your reply.
I've investigated the problem further here now that I'm back home with
access to my Lager board, but have been unable to reproduce it even by
testing all sync signal polarities.
First of all, the "CMA enabled" kernel configuration file attached to a
previous e-mail in this series indeed enables CMA, but doesn't enable
CMA usage for DMA buffers. You need to additionally set
CONFIG_DMA_CMA=y
CONFIG_CMA_SIZE_MBYTES=128
The amount of CMA memory to reserve can vary depending on the tests you
perform. The larger the resolutions and the number of buffers are, the
more memory you will need. 128MB should be a safe bet for most cases.
Feel free to reduce that if you need to use a lot of memory outside of
CMA, or increase it if you run into buffer allocation failures with
multimedia devices (DU, VIN, VSP, ...). You can then let the HDMI cable
plugged at all time and you should not get framebuffer allocation
failures when booting the board with the cable plugged in.
Then, I tried to modify the H/V sync polarities by using different video
modes. If you look at the output of "modetest -M rcar-du", you should
get a list of modes similar to the following for the HDMI output.
1440x900 60 1440 1520 1672 1904 900 903 909 934 flags: nhsync,
pvsync
1280x1024 75 1280 1296 1440 1688 1024 1025 1028 1066 flags: phsync,
pvsync
1280x1024 60 1280 1328 1440 1688 1024 1025 1028 1066 flags: phsync,
pvsync
1440x900 75 1440 1536 1688 1936 900 903 909 942 flags: nhsync,
pvsync
1280x800 60 1280 1328 1360 1440 800 803 809 823 flags: phsync,
nvsync
1152x864 75 1152 1216 1344 1600 864 865 868 900 flags: phsync,
pvsync
1024x768 75 1024 1040 1136 1312 768 769 772 800 flags: phsync,
pvsync
1024x768 70 1024 1048 1184 1328 768 771 777 806 flags: nhsync,
nvsync
1024x768 60 1024 1048 1184 1344 768 771 777 806 flags: nhsync,
nvsync
832x624 75 832 864 928 1152 624 625 628 667 flags: nhsync,
nvsync
800x600 75 800 816 896 1056 600 601 604 625 flags: phsync,
pvsync
800x600 72 800 856 976 1040 600 637 643 666 flags: phsync,
pvsync
800x600 60 800 840 968 1056 600 601 605 628 flags: phsync,
pvsync
800x600 56 800 824 896 1024 600 601 603 625 flags: phsync,
pvsync
640x480 75 640 656 720 840 480 481 484 500 flags: nhsync,
nvsync
640x480 73 640 664 704 832 480 489 492 520 flags: nhsync,
nvsync
640x480 67 640 704 768 864 480 483 486 525 flags: nhsync,
nvsync
640x480 60 640 656 752 800 480 490 492 525 flags: nhsync,
nvsync
720x400 70 720 738 846 900 400 412 414 449 flags: nhsync,
pvsync
Each mode has a defined horizontal and vertical polarity. If you pick
your modes carefully you will be able to test all four combinations of
polarities. I tried them all, and couldn't reproduce the reported
problem with the test procedure that Dong specified.
The easiest way to select a video mode for the fbdev compatibility layer
is to specify it as the default mode on the kernel command line using
the video= argument. The mode value is in the form of
<width>x<height>@<refresh rate>. For instance, to select the 1024x768
75Hz mode, simply add
video=1024x768@75
to the kernel command line arguments (there are multiple ways to do so
depending on how you configured your boot loader, I personally like to
modify the bootargs value in the .dts file for the board).
Could you please check if the problem occurs with all video modes
supported by your HDMI monitor or with some of them only ?
We have tried to configure our test environment based on your
explanation, then tested it again.
But It didn't work. (we tried all of video parameters
<width>x<height>@<refresh rate> we have )
And we tried to confirm the issue on Simon's tree of renesas-backport
bsp v3.10.31-rcar-gen2-1.9.9.
It worked with the same test method.
Did you check the issue on Upstream mainline version? or your own tree?
I tested both my own tree and mainline v4.10-rc2.
Could you attach your config file?
I was wondering that your config and ours might be different.
Sure. The configuration is based on the CONFIG_CMA_ENABLE.txt sent by Dong
in this mail thread, with the following changes.
--- CONFIG_CMA_ENABLE.txt 2017-02-17 15:21:57.974816277 +0200
+++ .config 2017-02-17 15:20:31.618818828 +0200
@@ -872,7 +872,17 @@
CONFIG_REGMAP_IRQ=y
CONFIG_DMA_SHARED_BUFFER=y
# CONFIG_DMA_FENCE_TRACE is not set
-# CONFIG_DMA_CMA is not set
+CONFIG_DMA_CMA=y
+
+#
+# Default contiguous memory area size:
+#
+CONFIG_CMA_SIZE_MBYTES=128
+CONFIG_CMA_SIZE_SEL_MBYTES=y
+# CONFIG_CMA_SIZE_SEL_PERCENTAGE is not set
+# CONFIG_CMA_SIZE_SEL_MIN is not set
+# CONFIG_CMA_SIZE_SEL_MAX is not set
+CONFIG_CMA_ALIGNMENT=8
#
# Bus devices
Thanks for your config file.
We have tested it on our test environments and using many difference
options of video parameters.
But It still didn't work.
Could you show me your rootfs's name and version?.
I use a buildroot-based rootfs with a custom configuration. I don't think the
rootfs makes a difference here, I would instead suspect that the issue is
related to the HDMI monitor. Would you be able to try a different screen ?
We have used three different screens we have.
Dell s2240L, Panasonic TH-L 19C3 and LG 23MP48HQ-P.
In there, Dell and LG screens are quite new.
What kind of screen are you using?
Thank you.
Hiep.
