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Dual display support in Omap5

Ishaqe Ahamed
Intellectual 645 points

Hi,

I need to add two displays LCD and HDMI to OMAP5  custom board.

The data from the GFX pipeline should be sent  to LCD1 and TV. Is it possible to  configure in that way ?

  • 0
    TI__Guru**** 161600 points

    Hello,

    Yes you can configure omap5 to have 2 displays. See Figure 10-2. Display Subsystem Environment:

     

    To have LCD & TV at the same time, you can connect the LCD to the primary DSI_PHY_DSS_A & the TV to the HDMI_PHY.

    Best Regards,
    Yordan

  • 0 in reply to Yordan Kovachev
    Intellectual 645 points

     

     

    Hi Yordan

    Thanks for the reply.

    I need know is it possible to configure the Graphics pipeline connected into  both VP_LCD1  and  VP_TV  ?

    We need to have two graphics path

    First out path:  GFX -> TV-> HDMI

    Second path:  GFX -> LCD1 -> DPI

    Is it possible or what are the alternatives ?

     

     

     Regards,

    Ishaqe

     

  • 0 in reply to Ishaqe Ahamed
    TI__Guru**** 161600 points

    Hi Ishaqe,

    Sorry I misunderstood your question.

    OMAP supports up to 3 LCD displays & TV out, but you cannot output GFX to both LCD1 and TV out.
    The selection is done using DISPC_GFX_ATTRIBUTES[8] CHANNELOUT & DISPC_GFX_ATTRIBUTES[31:30] CHANNELOUT2 bit fields.

    In CHANNELOUT2 bit field description it is stated that once you set CHENNELOUT to 0x1 (TV out selected) then you cannot set any of the LCDs as outputs to the GFX input (the CHANNELOUT2 bit field becomes reserved). 
    Meaning that you can connect GFX to only one of the following: LCD1, LCD2, LCD3 or TV.

    This is confirmed also by Table 10-48. DISPC Pipeline Connection to LCD, TV, or WB Output and the note bellow that table: "NOTE: When CHANNELOUT = 0x1, the settings CHANNELOUT2 = 0x0, 0x1, 0x2, and 0x3 are reserved.". See Section 10.2.4.12.1 DISPC Overlay Manager in OMAP5432 TRM.

    Best Regards,
    Yordan

  • 0 in reply to Yordan Kovachev
    Intellectual 645 points

    Thanks Yordan for the clarification.

    So to use dual display TV-> HDMI and LCD1 -> DPI, I need to use

    VID1 pipeline - >  LCD1  

    and 

    GFX  pipeline -> TV-> HDMI

  • 0 in reply to Ishaqe Ahamed
    TI__Guru**** 161600 points

    Ishaqe,


    Yes, your understanding is correct.

    A pipeline can be directed to only one output.

    Best Regards,

    Yordan

  • 0 in reply to Yordan Kovachev
    Intellectual 645 points

    Hi Yordan,
    As looking at the release note for latest GLSDK for OMAP5 from http://processors.wiki.ti.com/index.php/OMAP5_GLSDK_6.04.00.02_Release_Notes, it says multiple display support

    - Wayland, with Weston compositor, multiple display support
    - X11 stack, with OpenBox window manager, multiple display support

    Do you know how omapdss is configured to support multiple display in above cases as GFX cannot be given to LCD and TV at the same time? Or Is this using different pipeline?
    Please clarify on this

    Also from OMAP5 developer guide from http://processors.wiki.ti.com/index.php/OMAP5_GLSDK_Software_Developers_Guide , I read
    “Starting from GLSDK 6.04, the supported Wayland/Weston version is 1.3.0 which brings in the multiple display support in extended desktop mode and the ability to drag-and-drop windows from one display to the other.”
    Is multiple display support tested on OMAP5 which is running two different accelerated graphics application running on two different display?

     

    Regards,
    Ishaqe

  • 0 in reply to Ishaqe Ahamed
    TI__Guru**** 161600 points

    Hi Ishaqe,

    The GLSDK6_04 release is only for DRA7xx devices, see glsdk download page : http://downloads.ti.com/dsps/dsps_public_sw/glsdk/ , there is a mistake (probably because of reuse of the sources) in the wiki pages.

    The latest release for OMAP5 is GLSDK6_03: http://processors.wiki.ti.com/index.php/OMAP5_GLSDK_6.03.00.01_Release_Notes

    Useful information about GLSDK6_03 release, such as Release Notes, FAQs and Datasheet, can be found on the following page:

    http://processors.wiki.ti.com/index.php/Category:GLSDK

    Best Regards,
    Yordan

     

  • 0 in reply to Yordan Kovachev
    TI__Guru**** 161600 points

    Hi Ishaqe,

    Sorry for the misunderstanding. I've made a mistake. The latest GLSDK6_04 supports both devices DRA7xx and OMAP5.  At first it was released only for DRA evm, hence the confusion. 

    I haven't tested this release on my board, yet. I'll look at the code and post what I've found.

    It is most likely that  different pipelines are used for multiple display support, because of the restriction regarding pipelines described in OMAP5 TRM.

    Again sorry for the confusion.

    Best Regards,

    Yordan

  • 0 in reply to Yordan Kovachev
    Intellectual 645 points

    Hi Yordan,

    Thanks for clarifying.

    Please let me know once you have checked the code ,which the pipelines used for  multiple display support in the OMAP5.

     

    Regards,

    Ishaqe 

  • 0 in reply to Ishaqe Ahamed
    TI__Guru**** 161600 points

    Hello Ishaqe,

    The GLSDK display settings meet the description in TRM. Different pipelines are used for outputs.

    By default, as I got from the code, the HDMI (DIGITAL TV) , the primariy LCD & LCD2 paths are enabled. You can check the settings board-support/linux/drivers/video/omap2/dss (check dispc.c, display.c, omapdss.c files) & board-support/linux/drivers/gpu/drm , board-support/linux/drivers/gpu/drm/omapdrm.  

    For multiple display support different planes & FBs are used. 

    Best Regards,

    Yordan

  • 0 in reply to Yordan Kovachev
    Intellectual 645 points

    Hi Yordan,

    Thanks for the update 

    " For multiple display support different planes & FBs are used."

    Looking at KMS based application drm_extended and drm_clone source, yes planes and FBs are used.

    But, How the planes and FBs are used to support multiple display in X11 and Wayland? If possible could you please point me to the code changes for this?

    Which are the components which needed modification for this (Xserver, X11 DDX driver, Wayland, Window Manager – Open Box, omapdrm, omapdss etc)?

    Regards,

    Ishaqe 

  • 0 in reply to Ishaqe Ahamed
    Expert 1285 points

    Hi Yordan,

    As I am working on rendering via two different application to two different buuffer/fb  (usinf omapdrm driver )and get it displayed on two different displays, could you please give your suggestions/inputs/ideas for above post? Itwould be very helpful to me.

    Regards,

    Vikash