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drm/i915/vga: Register vgaarb client later

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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 <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20251208182637.334-2-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
This commit is contained in:
Ville Syrjälä 2025-12-08 20:26:19 +02:00
parent 37d5f4da49
commit 70ea362b84
3 changed files with 10 additions and 17 deletions
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18
drivers/gpu/drm/i915/display/intel_display_driver.c
View File

@ -208,16 +208,12 @@ 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);
@ -229,7 +225,7 @@ 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);
@ -301,11 +297,9 @@ 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);
@ -554,6 +548,8 @@ 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);
@ -646,8 +642,6 @@ 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);
}
@ -675,6 +669,8 @@ void intel_display_driver_unregister(struct intel_display *display)
acpi_video_unregister();
intel_opregion_unregister(display);
intel_vga_unregister(display);
}
/*

7
drivers/gpu/drm/i915/display/intel_vga.c
View File

@ -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)

2
drivers/gpu/drm/i915/display/intel_vga.h
View File

@ -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__ */