LVDS LCD no clock

[Korneliusz Osmenda]

Hi,

I'm trying to run linux on my tablet. (K1001L1C)

I have probed PD7 pin to get know what is going on.

On android I get 52MHz LVDS signal.

On linux-sunxi I get high LVDS state (1,4V)

I tried to tweak fex file but I haven't got anywhere.

Regards.

Korneliusz Osmenda

[Luc Verhaegen]

http://linux-sunxi.org/index.php?search=K1001L1C&title=Special%3ASearch

reveals nothing.

Are you working through the http://linux-sunxi.org/New_Device_howto at
all?

Luc Verhaegen.

[Korneliusz Osmenda]

There are support files in sunxi-boards and sunxi-uboot.

Now I have added basic wiki page (sorry that I haven't done sooner)

I use sunxi-bsp to make hwpack.

I use sunxi-v3.4.75-r0-1-g9cfbbed kernel

[Luc Verhaegen]

On Mon, Jan 06, 2014 at 07:21:14AM -0800, Korneliusz Osmenda wrote:
>
> There are support files in sunxi-boards and sunxi-uboot.
> Now I have added basic wiki page (sorry that I haven't done sooner)
> I use sunxi-bsp to make hwpack.
> I use sunxi-v3.4.75-r0-1-g9cfbbed kernel

Please do spend a bit more time on that page. There are way too many
people who bring their device up for themselves, go through a load of
trouble, and then, instead of spending an hour giving something back.

Imho, we should start actively ignoring people who haven't bothered
running through the new device howto properly, and leave them to fend
for themselves.

This device seems to properly use LVDS (lcd_if = 3). Interesting. My
hyundai a7hd claims to use the same, but it has the full PIO D port
listed. Whereas yours only lists PD0-9.

One thing worth noting is that your fex set the gpio muxes to 3, whereas
all other devices set it to 2. You might actually have a proper LVDS
panel whereas the others are all lying (but need a bit of extra support
from the LVDS controller to run).

It could very well be that proper LVDS support is broken in our kernel.
It seems that i must get my hands on this hw.

Luc Verhaegen.

[Korneliusz Osmenda]

Interestingly in disp_lcd.c in function Disp_lcdc_pin_cfg there is logic which likely fixes broken fex when mul_sel is wrong for LVDS. I have found it when I was trying to get it to work. On wiki cubieboard/LVDS there are wrongly selected muxes. This was spark to find this info in sources. Also I have checked PLL settings, and crosscheck LCDC settings with android. Nothing interesting found. I have something missed.

Korneliusz Osmenda

[Michal Suchanek]

Goerge Ioakimedes (the baseboard guy) has some LVDS lcds in his shop
and presumably has them working on a10. So maybe at some point in
time this actually worked.

Thanks

Michal

[Luc Verhaegen]

On Mon, Jan 06, 2014 at 05:41:27PM +0100, Michal Suchanek wrote:
>
> Goerge Ioakimedes (the baseboard guy) has some LVDS lcds in his shop
> and presumably has them working on a10. So maybe at some point in
> time this actually worked.

Could be, and could be that it still works on A10, with the right
script.bin. Could also be that this is like the supposed LVDS panels on
all other supposed LVDS based tablets, and that it really is just
switched to LCD.

Imho this makes this very interesting hw that's going to need some
special attention.

Luc Verhaegen.

[Luc Verhaegen]

On Mon, Jan 06, 2014 at 08:18:03AM -0800, Korneliusz Osmenda wrote:
>

Do fill out that page more, and get us some pictures.

Luc Verhaegen.

[Korneliusz Osmenda]

Camera in my phone cannot focus on glossy display and case. I will need get camera to get pictures of it. Also tided up.

Korneliusz Osmeda

[Luc Verhaegen]

Thanks.

Yeah, my pictures are with a phone too. Could be better but already
infinitely better than nothing.

Luc Verhaegen.

[Michal Suchanek]

Actually, VGA also worked on a10 but never got it working on CT with
sunxi. It works with the original image but no signal with sunxi and I
don't even have a scope here.

Thanks

Michal

[Dmitriy B.]

Interesting detail is, OLIMEX now sells LVDS panel https://www.olimex.com/Products/OLinuXino/A20/A20-LCD15.6/ http://olimex.wordpress.com/2013/12/09/new-product-in-stock-monster-lvds-15-6-lcd-for-a20-olinuxino/

They claim that it works with A20-OLinuXino-MICRO.

[TsvetanUsunov]

LVDS works, but as I reported a month ago LVDS driver is buggy, if the LVDS is one channel clock is OK, if the LVDS is two channels (like for Full HD 1980x1080p LCDs) the clock gets divided by the number of the channels which is wrong and we fix this manually by writing directly in PLL registers

Tsvetan

[Dmitriy B.]

2014/1/7 TsvetanUsunov

LVDS works, but as I reported a month ago LVDS driver is buggy

Thanks for rapid answer, but could you clarify, what kernel do you use? Our community one, or Allwinner SDK Android?

[TsvetanUsunov]

linux-sunxi 3.4.67+

[Luc Verhaegen]

On Mon, Jan 06, 2014 at 10:38:21PM -0800, TsvetanUsunov wrote:
> LVDS works, but as I reported a month ago LVDS driver is buggy, if the LVDS
> is one channel clock is OK, if the LVDS is two channels (like for Full HD
> 1980x1080p LCDs) the clock gets divided by the number of the channels which
> is wrong and we fix this manually by writing directly in PLL registers
> Tsvetan

Where was this reported?

Luc Verhaegen.

[TsvetanUsunov]

Where was this reported?

Luc Verhaegen.

do not remember, probably on IRC

Tsvetan 

[Michal Suchanek]

Hello,

On 7 January 2014 07:38, TsvetanUsunov <tsveta...@gmail.com> wrote:
> LVDS works, but as I reported a month ago LVDS driver is buggy, if the LVDS
> is one channel clock is OK, if the LVDS is two channels (like for Full HD
> 1980x1080p LCDs) the clock gets divided by the number of the channels which
> is wrong and we fix this manually by writing directly in PLL registers
> Tsvetan

Where does the division come from?

AFAICT the only place the number of channels is used is here:

drivers/video/sunxi/disp/de_lcdc.c:
(info->lcd_lvds_ch << 30) |

Thanks

Michal

>
> 07 януари 2014, вторник, 08:33:08 UTC+2, Dmitriy B. написа:
>>
>> Interesting detail is, OLIMEX now sells LVDS panel
>> https://www.olimex.com/Products/OLinuXino/A20/A20-LCD15.6/
>> http://olimex.wordpress.com/2013/12/09/new-product-in-stock-monster-lvds-15-6-lcd-for-a20-olinuxino/
>> They claim that it works with A20-OLinuXino-MICRO.
>

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[Korneliusz Osmenda]

Hello,

Trying to reproduce bug on cubieboard2 brought me a solution.

In fex file of my tablet there wasn't initialized pll3.

I will send this oneliner patch.

Korneliusz Osmenda

[George Ioakimedes]

Just to let you know I have tested many LVDS panels with both A10 and A20 as well as several kernels and have them working for more than 1 year now. I have not tested a dual channel (odd/even) in a long time so I can't say if the pixel clock is divided or not.

[hdev...@gmail.com]

> LVDS works, but as I reported a month ago LVDS driver is buggy, if the LVDS is one channel clock is OK, if the LVDS is two channels (like for Full HD 1980x1080p LCDs) the clock gets divided by the number of the channels which is wrong and we fix this manually by writing directly in PLL registers
> Tsvetan

Can you explain how you write directly in PLL registers and which values, to drive two channels LVDS ?

-Herve

[Kaspter Ju]

Hi all

LVDS two channels pannel can't works well, Can you explain how you write
directly in PLL registers and which values ?

many thanks.

-Kaspter

On 01/07/2014 02:38 PM, TsvetanUsunov wrote:
> LVDS works, but as I reported a month ago LVDS driver is buggy, if the
> LVDS is one channel clock is OK, if the LVDS is two channels (like for
> Full HD 1980x1080p LCDs) the clock gets divided by the number of the
> channels which is wrong and we fix this manually by writing directly in
> PLL registers
> Tsvetan
>
> 07 януари 2014, вторник, 08:33:08 UTC+2, Dmitriy B. написа:
>
> Interesting detail is, OLIMEX now sells LVDS panel
> https://www.olimex.com/Products/OLinuXino/A20/A20-LCD15.6/

> <https://www.olimex.com/Products/OLinuXino/A20/A20-LCD15.6/>
> http://olimex.wordpress.com/2013/12/09/new-product-in-stock-monster-lvds-15-6-lcd-for-a20-olinuxino/

> <http://olimex.wordpress.com/2013/12/09/new-product-in-stock-monster-lvds-15-6-lcd-for-a20-olinuxino/>
> They claim that it works with A20-OLinuXino-MICRO.
>

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Kaspter Ju

[George Ioakimedes]

I recently connected a 2 channel LVDS panel to Cubieboard2 (A20) and it worked well with just the normal FEX file changes.

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[Kaspter Ju]

Hi George,

thanks for your input, what kernel code did you use?
https://github.com/linux-sunxi/linux-sunxi.git branch sunxi-3.4?

thanks again,

Best Regards.

On 01/20/2015 10:32 PM, George Ioakimedes wrote:
> I recently connected a 2 channel LVDS panel to Cubieboard2 (A20) and it
> worked well with just the normal FEX file changes.
>
> On Mon, Jan 19, 2015 at 11:45 PM, Kaspter Ju <nigh0...@gmail.com
> <mailto:nigh0...@gmail.com>> wrote:
>
> Hi all
>
> LVDS two channels pannel can't works well, Can you explain how you
> write directly in PLL registers and which values ?
>
> many thanks.
>
> -Kaspter
>
> On 01/07/2014 02:38 PM, TsvetanUsunov wrote:
>
> LVDS works, but as I reported a month ago LVDS driver is buggy,
> if the
> LVDS is one channel clock is OK, if the LVDS is two channels
> (like for
> Full HD 1980x1080p LCDs) the clock gets divided by the number of the
> channels which is wrong and we fix this manually by writing
> directly in
> PLL registers
> Tsvetan
>
> 07 януари 2014, вторник, 08:33:08 UTC+2, Dmitriy B. написа:
>
> Interesting detail is, OLIMEX now sells LVDS panel

> https://www.olimex.com/__Products/OLinuXino/A20/A20-__LCD15.6/
> <https://www.olimex.com/Products/OLinuXino/A20/A20-LCD15.6/>
>
> <https://www.olimex.com/__Products/OLinuXino/A20/A20-__LCD15.6/
> <https://www.olimex.com/Products/OLinuXino/A20/A20-LCD15.6/>>
> http://olimex.wordpress.com/__2013/12/09/new-product-in-__stock-monster-lvds-15-6-lcd-__for-a20-olinuxino/
> <http://olimex.wordpress.com/2013/12/09/new-product-in-stock-monster-lvds-15-6-lcd-for-a20-olinuxino/>
>
> <http://olimex.wordpress.com/__2013/12/09/new-product-in-__stock-monster-lvds-15-6-lcd-__for-a20-olinuxino/

> <http://olimex.wordpress.com/2013/12/09/new-product-in-stock-monster-lvds-15-6-lcd-for-a20-olinuxino/>>
> They claim that it works with A20-OLinuXino-MICRO.
>
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>
>
> --
> Kaspter Ju
>
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--
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[George Ioakimedes]

I don't have that system on the workbench right now but it was off of the 3.4 branch and pulled within the last few months. For reference here is the display portion of my FEX:

[disp_init]

disp_init_enable = 1

disp_mode = 4

screen0_output_type = 1

screen0_output_mode = 4

screen1_output_type = 3

screen1_output_mode = 4

fb0_framebuffer_num = 4

fb0_format = 10

fb0_pixel_sequence = 0

fb0_scaler_mode_enable = 1

fb1_framebuffer_num = 2

fb1_format = 10

fb1_pixel_sequence = 0

fb1_scaler_mode_enable = 1

lcd0_bright = 197

lcd1_bright = 197

lcd0_screen_bright = 50

lcd0_screen_contrast = 50

lcd0_screen_saturation = 57

lcd0_screen_hue = 50

lcd1_screen_bright = 50

lcd1_screen_contrast = 50

lcd1_screen_saturation = 57

lcd1_screen_hue = 50

[lcd0_para]

lcd_used = 1

lcd_x = 1920

lcd_y = 1080

lcd_dclk_freq = 69

lcd_pwm_not_used = 0

lcd_pwm_ch = 0

lcd_pwm_freq = 10000

lcd_pwm_pol = 0

lcd_if = 3

lcd_hbp = 160

lcd_ht = 2084

lcd_vbp = 31

lcd_vt = 2226

lcd_hv_if = 0

lcd_hv_smode = 0

lcd_hv_s888_if = 0

lcd_hv_syuv_if = 0

lcd_hv_vspw = 0

lcd_hv_hspw = 0

lcd_lvds_ch = 1

lcd_lvds_mode = 0

lcd_lvds_bitwidth = 1

lcd_lvds_io_cross = 0

lcd_cpu_if = 0

lcd_frm = 1

lcd_io_cfg0 = 268435456

lcd_gamma_correction_en = 0

lcd_gamma_tbl_0 = 0x0

lcd_gamma_tbl_1 = 0x10101

lcd_gamma_tbl_255 = 0xffffff

lcd_bl_en_used = 1

lcd_bl_en = port:PH07<1><0><default><1>

lcd_power_used = 1

lcd_power = port:PH08<1><0><default><1>

lcd_pwm_used = 1

lcd_pwm = port:PB02<2><0><default><default>

[Kaspter Ju]

thank you George,

After some testing, 2 channel LVDS panel worked well if i disable lvds
output in uboot, hope this help others.

> https://github.com/linux-__sunxi/linux-sunxi.git

> <https://github.com/linux-sunxi/linux-sunxi.git> branch sunxi-3.4?
>
> thanks again,
>
> Best Regards.
>
> On 01/20/2015 10:32 PM, George Ioakimedes wrote:
>
> I recently connected a 2 channel LVDS panel to Cubieboard2 (A20)
> and it
> worked well with just the normal FEX file changes.
>
> On Mon, Jan 19, 2015 at 11:45 PM, Kaspter Ju
> <nigh0...@gmail.com <mailto:nigh0...@gmail.com>

> <mailto:nigh0...@gmail.com <mailto:nigh0...@gmail.com>>__>

> wrote:
>
> Hi all
>
> LVDS two channels pannel can't works well, Can you explain
> how you
> write directly in PLL registers and which values ?
>
> many thanks.
>
> -Kaspter
>
> On 01/07/2014 02:38 PM, TsvetanUsunov wrote:
>
> LVDS works, but as I reported a month ago LVDS driver
> is buggy,
> if the
> LVDS is one channel clock is OK, if the LVDS is two
> channels
> (like for
> Full HD 1980x1080p LCDs) the clock gets divided by the
> number of the
> channels which is wrong and we fix this manually by writing
> directly in
> PLL registers
> Tsvetan
>
> 07 януари 2014, вторник, 08:33:08 UTC+2, Dmitriy B. написа:
>
> Interesting detail is, OLIMEX now sells LVDS panel

> https://www.olimex.com/____Products/OLinuXino/A20/A20-____LCD15.6/
> <https://www.olimex.com/__Products/OLinuXino/A20/A20-__LCD15.6/>
>
> <https://www.olimex.com/__Products/OLinuXino/A20/A20-__LCD15.6/
> <https://www.olimex.com/Products/OLinuXino/A20/A20-LCD15.6/>>
>
>
> <https://www.olimex.com/____Products/OLinuXino/A20/A20-____LCD15.6/
> <https://www.olimex.com/__Products/OLinuXino/A20/A20-__LCD15.6/>
>
> <https://www.olimex.com/__Products/OLinuXino/A20/A20-__LCD15.6/
> <https://www.olimex.com/Products/OLinuXino/A20/A20-LCD15.6/>>>
> http://olimex.wordpress.com/____2013/12/09/new-product-in-____stock-monster-lvds-15-6-lcd-____for-a20-olinuxino/
> <http://olimex.wordpress.com/__2013/12/09/new-product-in-__stock-monster-lvds-15-6-lcd-__for-a20-olinuxino/>
>
> <http://olimex.wordpress.com/__2013/12/09/new-product-in-__stock-monster-lvds-15-6-lcd-__for-a20-olinuxino/
> <http://olimex.wordpress.com/2013/12/09/new-product-in-stock-monster-lvds-15-6-lcd-for-a20-olinuxino/>>
>
>
> <http://olimex.wordpress.com/____2013/12/09/new-product-in-____stock-monster-lvds-15-6-lcd-____for-a20-olinuxino/
> <http://olimex.wordpress.com/__2013/12/09/new-product-in-__stock-monster-lvds-15-6-lcd-__for-a20-olinuxino/>

>
> <http://olimex.wordpress.com/__2013/12/09/new-product-in-__stock-monster-lvds-15-6-lcd-__for-a20-olinuxino/
> <http://olimex.wordpress.com/2013/12/09/new-product-in-stock-monster-lvds-15-6-lcd-for-a20-olinuxino/>>>
> They claim that it works with A20-OLinuXino-MICRO.
>
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> Kaspter Ju
>
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> --
> Kaspter Ju
>
>

--
Kaspter Ju

[azh...@gmail.com]

Dear Kaspter,
Could You explain how did You disable lvds in u-boot?
I have the exatly same problem, with my olimex a20 som,
I dont have lvds clock, just constant high signal.

Thanks in advance
Attila HOFFEREK

[Kaspter Ju]

Hi Attila,

Just comment out CONFIG_SUNXI_DISPLAY

--- a/u-boot-2011.09/include/configs/sun7i.h
+++ b/u-boot-2011.09/include/configs/sun7i.h
@@ -150,7 +150,7 @@
#define CONFIG_CMD_BOOTA
#define CONFIG_SUN7I_DMA
#define CONFIG_CMD_MEMORY
-#define CONFIG_SUNXI_DISPLAY
+//#define CONFIG_SUNXI_DISPLAY

#define CONFIG_SUNXI_AXP20
#define CONFIG_SUNXI_AXP_MAIN PMU_TYPE_20X

--
Kaspter Ju

[Attila Hofferek]

Dear Kaspter

I'm afraid I can't comment it out, I couldn't find any CONFIG_SUNXI_DISPLAY define in my u-boot source tree.

I use this version: git clone https://github.com/RobertCNelson/u-boot

I grepped like this: cd u-boot; grep -r CONFIG_SUNXI_DISPLAY *

Have You got any idea, or could You offer me another version, where I can find the define metioned by You?

Thanks in advance

Yours sincerely

-- 

Attila HOFFEREK