Hi Jani, Thank you for the feedback.
> Which platforms? This should not be the case. The platform in question is a BTL-S RVP - a desktop board with no internal eDP panel physically wired. The BIOS/VBT incorrectly declares an eDP connector present, causing intel_edp_init_connector() to repeatedly time out on AUX A before giving up. This is confirmed by i915_display_info (no eDP connector listed) and dmesg ( several AUX A errors, ending with "failed to retrieve link info, disabling eDP"). > I'm not fine with adding module parameters for regular use cases. If there > are issues out there, they should be root caused and fixed, worst case with a > quirk. > You can also disable connectors using the video= parameter and connector name. Point taken. I will drop the new module parameter. The VBT is clearly a mismatch for this board. Rather than adding a new module parameter or DMI quirk, I would like to pursue your suggestion of fixing the existing video=eDP-1:d path (tested: not working for this case). May I rework that? > Please file a bug as described at [1], and be sure to attach the dmesg with > debugs, and the VBT. Bug filed with dmesg and raw VBT. https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16546 Thanks again for the direction. Best regards, Mei Fan -----Original Message----- From: Jani Nikula <[email protected]> Sent: Tuesday, 30 June 2026 6:47 pm To: Liou, Mei Fan <[email protected]>; Vivi, Rodrigo <[email protected]> Cc: Joonas Lahtinen <[email protected]>; Tvrtko Ursulin <[email protected]>; David Airlie <[email protected]>; Simona Vetter <[email protected]>; [email protected]; [email protected]; [email protected]; [email protected]; Liou, Mei Fan <[email protected]> Subject: Re: [PATCH] drm/i915: add disable_edp module parameter to skip phantom eDP init On Tue, 30 Jun 2026, [email protected] wrote: > From: "LIOU, Mei Fan" <[email protected]> > > Some platforms have BIOS/VBT that declares an eDP panel present while > no physical panel is connected. This causes intel_edp_init_connector() > to spend ~6 seconds waiting on PPS power sequencer and AUX channel > timeouts before failing gracefully. Which platforms? This should not be the case. > Introduce a new boolean module parameter 'disable_edp' (default: > false) that allows users to skip eDP connector initialization > entirely. When set, the driver logs an informational message and > returns false early from intel_edp_init_connector(), bypassing all PPS/AUX > probing. I'm fine with adding module parameters for *debugging*. I'm not fine with adding module parameters for regular use cases. If there are issues out there, they should be root caused and fixed, worst case with a quirk, but roughly never with a new module parameter. You can also disable connectors using the video= parameter and connector name, e.g. video=eDP-1:d or something. Making this work (if it doesn't) should be preferred over adding new module parameters. And even here, root causing and fixing is preferred. > This is modeled after the existing 'disable_display' parameter and is > intended as a workaround for headless or display-less deployments > where the BIOS incorrectly advertises an internal panel. "headless" and "display-less" are super ambiguous, given the amount of possible alternatives. You might not have display IP at all, or you could have everything except a display connected, or everything in between. But VBT advertizing eDP but it not being connected is not a scenario that we should have, and either the VBT or the whole setup is bonkers. Please file a bug as described at [1], and be sure to attach the dmesg with debugs, and the VBT. BR, Jani. [1] https://drm.pages.freedesktop.org/intel-docs/how-to-file-i915-bugs.html > > Signed-off-by: LIOU, Mei Fan <[email protected]> > --- > drivers/gpu/drm/i915/display/intel_display_params.c | 3 +++ > drivers/gpu/drm/i915/display/intel_display_params.h | 1 + > drivers/gpu/drm/i915/display/intel_dp.c | 7 +++++++ > 3 files changed, 11 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_display_params.c > b/drivers/gpu/drm/i915/display/intel_display_params.c > index 2aed110c5b09..8d47d19b1667 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_params.c > +++ b/drivers/gpu/drm/i915/display/intel_display_params.c > @@ -102,6 +102,9 @@ > intel_display_param_named_unsafe(force_reset_modeset_test, bool, 0400, > intel_display_param_named(disable_display, bool, 0400, > "Disable display (default: false)"); > > +intel_display_param_named(disable_edp, bool, 0400, > + "Disable eDP panel init, skips PPS/AUX probing when VBT declares eDP > +but no panel is present (default: false)"); > + > intel_display_param_named(verbose_state_checks, bool, 0400, > "Enable verbose logs (ie. WARN_ON()) in case of unexpected hw state > conditions."); > > diff --git a/drivers/gpu/drm/i915/display/intel_display_params.h > b/drivers/gpu/drm/i915/display/intel_display_params.h > index b95ecf728daa..98ab0d753dab 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_params.h > +++ b/drivers/gpu/drm/i915/display/intel_display_params.h > @@ -41,6 +41,7 @@ struct drm_printer; > param(bool, load_detect_test, false, 0600) \ > param(bool, force_reset_modeset_test, false, 0600) \ > param(bool, disable_display, false, 0400) \ > + param(bool, disable_edp, false, 0400) \ > param(bool, verbose_state_checks, true, 0400) \ > param(bool, nuclear_pageflip, false, 0400) \ > param(bool, enable_dp_mst, true, 0600) \ diff --git > a/drivers/gpu/drm/i915/display/intel_dp.c > b/drivers/gpu/drm/i915/display/intel_dp.c > index 85d3aa3b9894..c6293a1b3840 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -7214,6 +7214,13 @@ static bool intel_edp_init_connector(struct intel_dp > *intel_dp, > if (!intel_dp_is_edp(intel_dp)) > return true; > > + if (display->params.disable_edp) { > + drm_info(display->drm, > + "[ENCODER:%d:%s] eDP disabled by module parameter, > skipping init\n", > + encoder->base.base.id, encoder->base.name); > + return false; > + } > + > /* > * On IBX/CPT we may get here with LVDS already registered. Since the > * driver uses the only internal power sequencer available for both -- Jani Nikula, Intel
