[M] Change in coreboot[main]: mb/google/dedede/var/boxy: Wait up for 3s for HPD ready signal

[Joey Peng (Code Review)]

Attention is currently required from: Derek Huang, Paul Menzel.

Joey Peng has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/78146?usp=email )

Change subject: mb/google/dedede/var/boxy: Wait up for 3s for HPD ready signal
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Patch Set 7:

(5 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/78146/comment/c7d49ebf_037ad7a8 :
PS5, Line 7: Add wait for HPD function
> Maybe: […]

Done

https://review.coreboot.org/c/coreboot/+/78146/comment/230bbd4e_360d59ef :
PS5, Line 9: need
> needs

Done

https://review.coreboot.org/c/coreboot/+/78146/comment/0f6937ad_f06b86e1 :
PS5, Line 9: Boxy project need to wait for HPD ready to continue boot in ramstage to
           : avoid no display in DEV screen and recovery screen
> Please add a dot/period at the end of sentences.

Done

File src/mainboard/google/dedede/variants/boxy/ramstage.c:

https://review.coreboot.org/c/coreboot/+/78146/comment/a8315664_1a98cf2e :
PS5, Line 67: 	static const long display_timeout_ms = 3000;
> Why 3 seconds?

The three seconds is referenced form project puff.
Also we have tested the delay time needs to be more than 3 seconds to work on boxy.

https://review.coreboot.org/c/coreboot/+/78146/comment/7ab99979_523d4ca3 :
PS5, Line 69: if (display_init_required()
            : 		&& !gpio_get(GPIO_USB_C0_HPD)) {
            : 		/* This has to be done before FSP-S runs. */
            : 		if (google_chromeec_wait_for_displayport(display_timeout_ms)) {
            : 			wait_for_hpd(GPIO_USB_C0_HPD, display_timeout_ms);
            : 		}
            : 	} else if (display_init_required()
            : 		&& !gpio_get(GPIO_USB_C1_HPD)) {
            : 		/* This has to be done before FSP-S runs. */
            : 		if (google_chromeec_wait_for_displayport(display_timeout_ms)) {
            : 			wait_for_hpd(GPIO_USB_C1_HPD, display_timeout_ms);
            : 		}
            : 	}
> Can there be two displays attached at the same time?

We have 1 HDMI and 2 Type-C ports for boxy project.
This issue only happens when connected to Type-C dongle on DEV mode and recovery mode.
Normal mode boot or DEV mode/recovery mode via HDMI works fine.