About 1080p with LCD output on MX6Q

[RobbieJiang]

I'm working with MX6Q Sabrelite board and the latest BSP Ltib3.0.25_4.1.0.

And I would like to have LCD output in 1080p ( i.e, 1920x1080) mode.

The MX6Q reference manual states that 1080p is supported by hardware.

However, with this BSP, I can have LCD output in 1024x768, but not in 1920x1080.

Seems that current BSP does not support 1080p LCD output.

Does Freescale has any plan to support LCD in 1080p?

Or anyone else has successful experience in driving LCD ouput in 1080p mode?

[qiang_li-mpu_se]

I think you need check the frequency of PLL5 and IPU DI clock, when the issue happens.

The PLL5 frequency is configable to generate the correct pixel clock.

[davecbluechip]

I can confirm that this approach works. I have a similar mode (only 60Hz rather than 50Hz) and a similar arrangement using a DVI encoder (TFP410) and I get 1920x1080 on the DVI output.

My exact code is:

static struct fb_videomode lcdif_modedb[] = {

{

  /* 1920x1080 @ 60 Hz, pixel clock @ 148.5MHz */

  "1080p", 60, 1920, 1080, 6734, 88, 148, 2, 15, 44, 5,

  FB_SYNC_CLK_LAT_FALL ,

  FB_VMODE_NONINTERLACED,

  0,

  },

// Followed by the other modes

[RobbieJiang]

Thanks for your helpful replies.

After adding the 1080p@50Hz/1080p@60HZ modes to the lcdif_modedb[],

still there is no output on my DVI display.

However, we can measure that there are pixel clock and H/V sync signals

from the lcd interface. For example,  for  1080p@50HZ, the pixel clock is 120Mhz,

the Vsync is about 50Hz.  Does it imply that the LCD driver works correctly and

the output is OK?

If so, we can focus on the ADV7513 driver. Perhaps something is missing or wrong.

[davecbluechip]

Hi Robbie,

120MHz and 50Hz sounds about right. Is there any plausible activity on the data lines?

One thing that might be worth checking (it caught me out the first time I tried to get my TFP410 running) is the power status of the video transmitter chip. A quick glance at the driver code suggests that adv7511_probe() puts the chip into power-down state by default. Are you bringing it up somewhere?

Regards,

Dave C

[RobbieJiang]

Hi davebluechip

When working with your 1080p@60Hz mode,

I still can not get output on my DVI display.

And the 'fbset' command gives the following outputs:

root@freescale ~$  fbset

mode "1920x1080-61"

    # D: 148.500 MHz, H: 67.500 kHz, V: 61.252 Hz

    geometry 1920 1080 1920 1080 24

    timings 6734 88 148 2 15 44 5

    rgba 8/16,8/8,8/0,0/0

endmode

In my understanding, the Vsync signal should be 60Hz,not 61.25Hz.

Note this frequency is the same as what we have measured with oscilloscope.

Is this correct?

Could you please show me your outputs of fbset with 1080p@60Hz?

Also, we find that our adv7513 can not auto detect correctly  the input video identification( which should be 1080p-60).

Is it because of the potentially wrong Vsync frequency?

And my BSP is L3.0.35_4.1.0_130816.

How about yours?

By the way, I did power adv7513 up in my driver because I can get output on DVI display with 720p mode.

Thanks.

[EricNelson]

Hi Robbie,

No (I'm not sure). I was confused by the fact that you mentioned other modes working and thought you were working through HDMI. It is atypical of LVDS or PRGB displays to support multiple modes.

We haven't connected an 1080P LCD using the parallel LCD interface (mxc_lcdif). The clock rates involve are generally higher than you'll want to drive over this sort of cabling.

The parallel LCD interface is generally used for smaller displays (<= 1024x768).

What kind of display are you connecting? Have you double-checked all of the clock and margin parameters?

You may also want to verify the pixel clock, hsync, and vsync signals with a scope to see if they're clean.

[RobbieJiang]

Hi Eric,

We don't output 1080p directly to LCD device.

Actually we connect an  ADV7511  chip to the LCD interface,

ADV7511 can convert RGB24 to DVI signals,

so that we can have 1080p output on a DVI display device.

But by now, the latest BSP does not support 1080p with the LCD interface,

and of course, we can not get 1080p on the DVI device through LCD interface.

[EricNelson]

Hi Robbie,

Any time you add custom hardware to the platform, whether it's a new USB or PCIe device, or as in your case, a new display, you should be prepared to edit some kernel code.

My comments about signal integrity apply regardless of whether you're driving the display directly, or through an RGB->DVI

converter like the ADV7511.

In the ADV7511 case, you'll likely also need an I2C interface to control the interface.

Have you connected your display to the HDMI port?

[RobbieJiang]

Hi Eric,

We have developed the ADV7511 driver, and it works with LCD interface in 1040x768.

What is missing is LCD output in 1080p.

This is my problem.

If LCD display interface can work in 1080p, our ADV7511 can surely support it.

[EricNelson]

I understand.

Can you see and measure the HSYNC and VSYNC signals to see if you have proper clocking?

[RobbieJiang]

We have.

The pixclk, H/V sync  signals are all wrong.

[EricNelson]

Wrong how?