On Mon, 08 Dec 2025, Ville Syrjala <[email protected]> wrote: > From: Ville Syrjälä <[email protected]> > > Currently we register to vgaarb way too early. Thus it is > possible that the entire VGA decode logic gets nuked via > GMCH_CTRL before intel_vga_disable() has even disabled the > VGA plane. This could even cause a system hang because > we'll be unable to turn off the VGA plane gracefully. > > Move the vgaarb registration into intel_display_driver_register(). > I suppose we could do it a bit earlier (after intel_vga_disable()), > but not convinced there's any point. > > Also the error handling here is pointless since the > registration can't fail (unless the device isn't a VGA class > in which case all VGA decode logic should aleady be disabled > by the BIOS via GMCH_CTRL). But let's toss in a WARN to catch > any future breakage of vga_client_register(). > > Signed-off-by: Ville Syrjälä <[email protected]>
After this, intel_vga_register() is only called for HAS_DISPLAY(), while previously it was called unconditionally. It's probably fine? Other than that, Reviewed-by: Jani Nikula <[email protected]> > --- > .../drm/i915/display/intel_display_driver.c | 18 +++++++----------- > drivers/gpu/drm/i915/display/intel_vga.c | 7 ++----- > drivers/gpu/drm/i915/display/intel_vga.h | 2 +- > 3 files changed, 10 insertions(+), 17 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.c > b/drivers/gpu/drm/i915/display/intel_display_driver.c > index 7e000ba3e08b..b149976f527b 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_driver.c > +++ b/drivers/gpu/drm/i915/display/intel_display_driver.c > @@ -214,16 +214,12 @@ int intel_display_driver_probe_noirq(struct > intel_display *display) > > intel_bios_init(display); > > - ret = intel_vga_register(display); > - if (ret) > - goto cleanup_bios; > - > intel_psr_dc5_dc6_wa_init(display); > > /* FIXME: completely on the wrong abstraction layer */ > ret = intel_power_domains_init(display); > if (ret < 0) > - goto cleanup_vga; > + goto cleanup_bios; > > intel_pmdemand_init_early(display); > > @@ -235,7 +231,7 @@ int intel_display_driver_probe_noirq(struct intel_display > *display) > display->hotplug.dp_wq = alloc_ordered_workqueue("intel-dp", 0); > if (!display->hotplug.dp_wq) { > ret = -ENOMEM; > - goto cleanup_vga_client_pw_domain_dmc; > + goto cleanup_pw_domain_dmc; > } > > display->wq.modeset = alloc_ordered_workqueue("i915_modeset", 0); > @@ -307,11 +303,9 @@ int intel_display_driver_probe_noirq(struct > intel_display *display) > destroy_workqueue(display->wq.modeset); > cleanup_wq_dp: > destroy_workqueue(display->hotplug.dp_wq); > -cleanup_vga_client_pw_domain_dmc: > +cleanup_pw_domain_dmc: > intel_dmc_fini(display); > intel_power_domains_driver_remove(display); > -cleanup_vga: > - intel_vga_unregister(display); > cleanup_bios: > intel_bios_driver_remove(display); > > @@ -566,6 +560,8 @@ void intel_display_driver_register(struct intel_display > *display) > if (!HAS_DISPLAY(display)) > return; > > + intel_vga_register(display); > + > /* Must be done after probing outputs */ > intel_opregion_register(display); > intel_acpi_video_register(display); > @@ -658,8 +654,6 @@ void intel_display_driver_remove_nogem(struct > intel_display *display) > > intel_power_domains_driver_remove(display); > > - intel_vga_unregister(display); > - > intel_bios_driver_remove(display); > } > > @@ -687,6 +681,8 @@ void intel_display_driver_unregister(struct intel_display > *display) > > acpi_video_unregister(); > intel_opregion_unregister(display); > + > + intel_vga_unregister(display); > } > > /* > diff --git a/drivers/gpu/drm/i915/display/intel_vga.c > b/drivers/gpu/drm/i915/display/intel_vga.c > index c45c4bbc3f95..f13734cfd904 100644 > --- a/drivers/gpu/drm/i915/display/intel_vga.c > +++ b/drivers/gpu/drm/i915/display/intel_vga.c > @@ -135,7 +135,7 @@ static unsigned int intel_gmch_vga_set_decode(struct > pci_dev *pdev, bool enable_ > return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; > } > > -int intel_vga_register(struct intel_display *display) > +void intel_vga_register(struct intel_display *display) > { > > struct pci_dev *pdev = to_pci_dev(display->drm->dev); > @@ -150,10 +150,7 @@ int intel_vga_register(struct intel_display *display) > * vga_client_register() fails with -ENODEV. > */ > ret = vga_client_register(pdev, intel_gmch_vga_set_decode); > - if (ret && ret != -ENODEV) > - return ret; > - > - return 0; > + drm_WARN_ON(display->drm, ret && ret != -ENODEV); > } > > void intel_vga_unregister(struct intel_display *display) > diff --git a/drivers/gpu/drm/i915/display/intel_vga.h > b/drivers/gpu/drm/i915/display/intel_vga.h > index 16d699f3b641..80084265c6cd 100644 > --- a/drivers/gpu/drm/i915/display/intel_vga.h > +++ b/drivers/gpu/drm/i915/display/intel_vga.h > @@ -10,7 +10,7 @@ struct intel_display; > > void intel_vga_reset_io_mem(struct intel_display *display); > void intel_vga_disable(struct intel_display *display); > -int intel_vga_register(struct intel_display *display); > +void intel_vga_register(struct intel_display *display); > void intel_vga_unregister(struct intel_display *display); > > #endif /* __INTEL_VGA_H__ */ -- Jani Nikula, Intel
