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EDID Header Check Issue in intel_hdmi21_tx_edid_get_sink_status() function for intel_hdmi21 driver

dscully
Novice
988 Views

Hi,

 

I'd like to report a bug in the intel_hdmi21 driver as of Quartus Pro 23.2

 

See: intelFPGA_pro/23.2/ip/altera/altera_hdmi/hw_demo/common/software/software_driver/intel_hdmi21_tx/src/intel_hdmi21_tx_edid.c

 Consider the following function:

int intel_hdmi21_tx_edid_get_sink_status(intel_hdmi21_tx_instance_t* instance, uint8_t* edid_header_valid, uint32_t* edid_size)
{
    if (instance == NULL)
        return intel_hdmi_invalid_instance;
    if((edid_header_valid == NULL) || (edid_size == NULL))
        return intel_hdmi_invalid_arguments;

    uint32_t headerSize = 8;
    (*edid_header_valid) = 1;
    (*edid_size) = 0;
    for(uint32_t i = 0; i < headerSize; i++)
    {
        uint8_t val = edid_read_sink_reg(i);
        (*edid_header_valid) &= (((i == 0 || i == (headerSize - 1)) && val == 0) || (val == 0xFF)) ? 1 : 0;
    }

    if((*edid_header_valid))
    {
        const uint32_t numberOfExtensionsOffset = 126;
        uint32_t numberOfExtensions = edid_read_sink_reg(numberOfExtensionsOffset);
        (*edid_size) = (numberOfExtensions + 1) * INTEL_HDMI_EDID_BLOCK_SIZE;
    }

    return intel_hdmi_success;
}

The edid_head_valid check on 14 should only pass on a valid on the EDID header pattern of "00 FF FF FF FF FF FF 00". However, but will also pass a pattern of all 0xFF or a 0xFF in the first or last position due to the second logical OR in the expression.

 

Passing on all 0xFF is especially problematic as reading a I2C bus with an non-responding EDID device returns 0xFF for every byte. The result of the failure is that the header is declared valid and the EDID size is reported as 128 * 255.

 

The expected behavior is that the valid flag will be set properly.

 

Please let me know if there is a more appropriate place to report issues against the Intel FPGA BSP drivers.

 

Thank you,

David

 

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ZH_Intel
Employee
885 Views

Hi David,


Thank you for your patience.

Based on the discussion with our internal team, I believe that this is a bug and your concern is correct.

I will reported this to our internal team to be fix in future release.


This fix that you suggested is a valid fix/workaround for this issue.

 

Thank you.

Best Regards,

ZulsyafiqH_Intel


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dscully
Novice
958 Views

A possible fix would be to change:

(*edid_header_valid) &= (((i == 0 || i == (headerSize - 1)) && val == 0) || (val == 0xFF)) ? 1 : 0;

to

(*edid_header_valid) &= (((i == 0 || i == (headerSize - 1))) ? (val == 0) : (val == 0xFF)) ? 1 : 0;

 

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ZH_Intel
Employee
910 Views

Hi David,

 

Thank you for reaching out.

Just to let you know that Intel has received your support request and currently we are confirming the details with our internal team.

I shall come back to you with findings.

 

Thank you for your patience.

 

Best Regards,

ZulsyafiqH_Intel



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ZH_Intel
Employee
886 Views

Hi David,


Thank you for your patience.

Based on the discussion with our internal team, I believe that this is a bug and your concern is correct.

I will reported this to our internal team to be fix in future release.


This fix that you suggested is a valid fix/workaround for this issue.

 

Thank you.

Best Regards,

ZulsyafiqH_Intel


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dscully
Novice
807 Views

Thank you! I have marked this topic as resolved.

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ZH_Intel
Employee
770 Views

Hi David,

 

I’m glad that your question has been addressed, I now transition this thread to community support. If you have a new question, feel free to open a new thread to get the support from Intel experts. Otherwise, the community users will continue to help you on this thread.

Thank you.

 

Best Regards,

ZulsyafiqH_Intel



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