How to tune LCM parameters?

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alanli

I was adding a custom LCM module on Helio X20 Develpment board. Our custom LCM module is able to support FHD (1920x1080) with 60Hz.

However, the LCD is flicking when params->dsi.PLL_CLOCK = 450 (which is around 52Hz)
When I decreased params->dsi.PLL_CLOCK to 350 (which is around 42Hz), the LCD became normal without flicking again

Do you have any guidline for tuning the LCM parameters so that I could display FHD at 60Hz normally? Thanks in advance!

koncn

alanli

I am glad to see you have found a compatible LCM module to connect to X20 96Boards!

Could you please share the LCM module information for me? or some website links about it.

Regarding to your issue, did you connect the LCM module to the 60 pins high speed expansion connector of X20 96Boards? or you connect to X20 EVB?

BTW, please adb shell into the X20 96Boards, and dump the display info to let us investigate the issue deeply!
you can execute the command like this to get the output:

$ dumpsys display | grep DisplayInfo

Thank you!

alanli

I connected via 60 pins high speed expansion connector of X20 96Boards

The output from "dumpsys display|grep DisplayInfo" as below.

mBaseDisplayInfo=DisplayInfo{"Built-in Screen", uniqueId "local:0", app 1080 x 1920, real 1080 x 1920, largest app 1080 x 1920, smallest app 1080 x 1920, mode 1, defaultMode 1, modes [{id=1, width=1080, height=1920, fps=43.57}], rotation 0, density 480 (480.0 x 480.0) dpi, layerStack 0, appVsyncOff 0, presDeadline 23951572, type BUILT_IN, state ON, FLAG_SECURE, FLAG_SUPPORTS_PROTECTED_BUFFERS}

mOverrideDisplayInfo=DisplayInfo{"Built-in Screen", uniqueId "local:0", app 1080 x 1776, real 1080 x 1920, largest app 1794 x 1704, smallest app 1080 x 1008, mode 1, defaultMode 1, modes [{id=1, width=1080, height=1920, fps=43.57}], rotation 0, density 480 (480.0 x 480.0) dpi, layerStack 0, appVsyncOff 0, presDeadline 23951572, type BUILT_IN, state ON, FLAG_SECURE, FLAG_SUPPORTS_PROTECTED_BUFFERS}

alanli

We are using SSD2098 from Solomon Systech. The following are driver information we configured it on DSI0.

[660] [DISPCHECK]***** dump lcm driver information *****
[660] [DISPCHECK][LCM], name: ssd2098_fhd_dsi_cmd_solomon_rt4832_drv
[660] [DISPCHECK][LCM] resolution: 1080 x 1920
[660] [DISPCHECK][LCM] physical size: 0 x 0
[660] [DISPCHECK][LCM] physical size: 0 x 0
[660] [DISPCHECK][LCM] lcm_if:1, cmd_if:1
[660] [DISPCHECK][LCM] interface: DSI0
[660] [DISPCHECK][LCM] Type: DSI
[660] [DISPCHECK][LCM] DSI Mode: SYNC_EVENT_VDO_MODE
[660] [DISPCHECK][LCM] LANE_NUM: 4,data_format: 0,vertical_sync_active: 0
[680] [DISPCHECK][LCM] vact: 1, vbp: 159, vfp: 253, vact_line: 1920, hact: 4, hbp: 20, hfp: 20, hblank: 0, hactive: 1080
[680] [DISPCHECK][LCM] pll_select: 0, pll_div1: 0, pll_div2: 0, fbk_div: 0,fbk_sel: 0, rg_bir: 0
[680] [DISPCHECK][LCM] rg_bic: 0, rg_bp: 0, PLL_CLOCK: 370, dsi_clock: 0, ssc_range: 0, ssc_disable: 0, compatibility_for_nvk: 0, cont_clock: 0
[680] [DISPCHECK][LCM] lcm_ext_te_enable: 0, noncont_clock: 0, noncont_clock_period: 0
[740] [DISPCHECK][DDPDSI] DSI Mode: SYNC_EVENT_VDO_MODE
[740] [DISPCHECK][DDPDSI] LANE_NUM: 4,data_format: 0,vertical_sync_active: 0
[740] [DISPCHECK][DDPDSI] vact: 1, vbp: 159, vfp: 253, vact_line: 1920, hact: 4, hbp: 20, hfp: 20, hblank: 0, hblank: 1174883524
[740] [DISPCHECK][DDPDSI] pll_select: 0, pll_div1: 0, pll_div2: 0, fbk_div: 0,fbk_sel: 0, rg_bir: 0
[740] [DISPCHECK][DDPDSI] rg_bic: 0, rg_bp: 0, PLL_CLOCK: 370, dsi_clock: 0, ssc_range: 0, ssc_disable: 0, compatibility_for_nvk: 0, cont_clock: 0
[740] [DISPCHECK][DDPDSI] lcm_ext_te_enable: 0, noncont_clock: 0, noncont_clock_period: 0
[740] [DISP]func|DSI_PHY_clk_setting

alanli

If I added "params->dsi.clk_lp_per_line_enable = 1;", I could increase "params->dsi.PLL_CLOCK" from = 370 to 530;
(i.e. the frame rate increased from 43.57Hz to 54.29Hz)

Do you have other suggestions to achieve 60Hz?