Re: [PATCH] drm/xe: Rename enable_display module param

[Jani Nikula <jani.nikula@linux.intel.com>]

On Thu, 08 Aug 2024, Lucas De Marchi <lucas.demarchi@intel.com> wrote:
> The different approach used by xe regarding the initialization of
> display HW has been proved a great additional for early driver bring up:
> core xe can be tested without having all the bits sorted out on the
> display side.
>
> On the other hand, the approach exposed by i915-display is to *actively*
> disable the display by programming it if needed, i.e. if it was left
> enabled by firmware. It also has its use to make sure the HW is actually
> disabled and not wasting power.
>
> However having both the way it is in xe doesn't expose a good interface
> wrt module params. From modinfo:
>
> 	disable_display:Disable display (default: false) (bool)
> 	enable_display:Enable display (bool)
>
> Rename enable_display do probe_display to try to convey the message that

*to

> the HW is being touched and improve the module param description. To
> avoid confusion, the enable_display is renamed everywhere, not only in
> the module param. New description for the parameters:
>
> 	disable_display:Disable display (default: false) (bool)
> 	probe_display:Probe display HW, otherwise it's left untouched (default: true) (bool)
>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

Acked-by: Jani Nikula <jani.nikula@intel.com>

> ---
>
> Now that xe settled in upstream, maybe it's also time to consider
> removing the CONFIG_DRM_XE_DISPLAY as discussed in
> https://lore.kernel.org/all/oedsuayuo3wtdea6cvmzaoesji25bwbqohgemayj5ocybbzgtn@el2d34rwqfsn/

I think CONFIG_DRM_XE_DISPLAY=n is a legit use case for people without
display hardware wanting to use a smaller footprint driver (typically
servers).

> Also relevant: https://lore.kernel.org/all/87sfer1fjj.fsf@intel.com/
>
> Jani, I think at one point you had a patch to remove enable_display
> (which I was against and still am for the reasons above) or rename it
> (what this patch is doing). However I couldn't find it to check if you
> were trying to rename to a similar thing as I'm doing now.

I think I just misunderstood your use case, in part because of the
naming. So thanks for fixing it. :)

>  drivers/gpu/drm/xe/display/xe_display.c | 46 ++++++++++++-------------
>  drivers/gpu/drm/xe/xe_device.c          |  2 +-
>  drivers/gpu/drm/xe/xe_device_types.h    |  7 ++--
>  drivers/gpu/drm/xe/xe_module.c          |  6 ++--
>  drivers/gpu/drm/xe/xe_module.h          |  2 +-
>  drivers/gpu/drm/xe/xe_pci.c             |  8 ++---
>  6 files changed, 37 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/display/xe_display.c b/drivers/gpu/drm/xe/display/xe_display.c
> index ca4468c82078..e30fb482d542 100644
> --- a/drivers/gpu/drm/xe/display/xe_display.c
> +++ b/drivers/gpu/drm/xe/display/xe_display.c
> @@ -46,7 +46,7 @@ static bool has_display(struct xe_device *xe)
>   */
>  bool xe_display_driver_probe_defer(struct pci_dev *pdev)
>  {
> -	if (!xe_modparam.enable_display)
> +	if (!xe_modparam.probe_display)
>  		return 0;
>  
>  	return intel_display_driver_probe_defer(pdev);
> @@ -62,7 +62,7 @@ bool xe_display_driver_probe_defer(struct pci_dev *pdev)
>   */
>  void xe_display_driver_set_hooks(struct drm_driver *driver)
>  {
> -	if (!xe_modparam.enable_display)
> +	if (!xe_modparam.probe_display)
>  		return;
>  
>  	driver->driver_features |= DRIVER_MODESET | DRIVER_ATOMIC;
> @@ -104,7 +104,7 @@ static void xe_display_fini_nommio(struct drm_device *dev, void *dummy)
>  {
>  	struct xe_device *xe = to_xe_device(dev);
>  
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	intel_power_domains_cleanup(xe);
> @@ -112,7 +112,7 @@ static void xe_display_fini_nommio(struct drm_device *dev, void *dummy)
>  
>  int xe_display_init_nommio(struct xe_device *xe)
>  {
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return 0;
>  
>  	/* Fake uncore lock */
> @@ -128,7 +128,7 @@ static void xe_display_fini_noirq(void *arg)
>  {
>  	struct xe_device *xe = arg;
>  
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	intel_display_driver_remove_noirq(xe);
> @@ -139,7 +139,7 @@ int xe_display_init_noirq(struct xe_device *xe)
>  {
>  	int err;
>  
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return 0;
>  
>  	intel_display_driver_early_probe(xe);
> @@ -170,7 +170,7 @@ static void xe_display_fini_noaccel(void *arg)
>  {
>  	struct xe_device *xe = arg;
>  
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	intel_display_driver_remove_nogem(xe);
> @@ -180,7 +180,7 @@ int xe_display_init_noaccel(struct xe_device *xe)
>  {
>  	int err;
>  
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return 0;
>  
>  	err = intel_display_driver_probe_nogem(xe);
> @@ -192,7 +192,7 @@ int xe_display_init_noaccel(struct xe_device *xe)
>  
>  int xe_display_init(struct xe_device *xe)
>  {
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return 0;
>  
>  	return intel_display_driver_probe(xe);
> @@ -200,7 +200,7 @@ int xe_display_init(struct xe_device *xe)
>  
>  void xe_display_fini(struct xe_device *xe)
>  {
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	intel_hpd_poll_fini(xe);
> @@ -211,7 +211,7 @@ void xe_display_fini(struct xe_device *xe)
>  
>  void xe_display_register(struct xe_device *xe)
>  {
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	intel_display_driver_register(xe);
> @@ -221,7 +221,7 @@ void xe_display_register(struct xe_device *xe)
>  
>  void xe_display_unregister(struct xe_device *xe)
>  {
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	intel_unregister_dsm_handler();
> @@ -231,7 +231,7 @@ void xe_display_unregister(struct xe_device *xe)
>  
>  void xe_display_driver_remove(struct xe_device *xe)
>  {
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	intel_display_driver_remove(xe);
> @@ -241,7 +241,7 @@ void xe_display_driver_remove(struct xe_device *xe)
>  
>  void xe_display_irq_handler(struct xe_device *xe, u32 master_ctl)
>  {
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	if (master_ctl & DISPLAY_IRQ)
> @@ -250,7 +250,7 @@ void xe_display_irq_handler(struct xe_device *xe, u32 master_ctl)
>  
>  void xe_display_irq_enable(struct xe_device *xe, u32 gu_misc_iir)
>  {
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	if (gu_misc_iir & GU_MISC_GSE)
> @@ -259,7 +259,7 @@ void xe_display_irq_enable(struct xe_device *xe, u32 gu_misc_iir)
>  
>  void xe_display_irq_reset(struct xe_device *xe)
>  {
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	gen11_display_irq_reset(xe);
> @@ -267,7 +267,7 @@ void xe_display_irq_reset(struct xe_device *xe)
>  
>  void xe_display_irq_postinstall(struct xe_device *xe, struct xe_gt *gt)
>  {
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	if (gt->info.id == XE_GT0)
> @@ -286,7 +286,7 @@ static bool suspend_to_idle(void)
>  void xe_display_pm_suspend(struct xe_device *xe, bool runtime)
>  {
>  	bool s2idle = suspend_to_idle();
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	/*
> @@ -316,7 +316,7 @@ void xe_display_pm_suspend(struct xe_device *xe, bool runtime)
>  void xe_display_pm_suspend_late(struct xe_device *xe)
>  {
>  	bool s2idle = suspend_to_idle();
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	intel_power_domains_suspend(xe, s2idle);
> @@ -326,7 +326,7 @@ void xe_display_pm_suspend_late(struct xe_device *xe)
>  
>  void xe_display_pm_resume_early(struct xe_device *xe)
>  {
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	intel_display_power_resume_early(xe);
> @@ -336,7 +336,7 @@ void xe_display_pm_resume_early(struct xe_device *xe)
>  
>  void xe_display_pm_resume(struct xe_device *xe, bool runtime)
>  {
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		return;
>  
>  	intel_dmc_resume(xe);
> @@ -374,7 +374,7 @@ int xe_display_probe(struct xe_device *xe)
>  {
>  	int err;
>  
> -	if (!xe->info.enable_display)
> +	if (!xe->info.probe_display)
>  		goto no_display;
>  
>  	intel_display_device_probe(xe);
> @@ -387,7 +387,7 @@ int xe_display_probe(struct xe_device *xe)
>  		return 0;
>  
>  no_display:
> -	xe->info.enable_display = false;
> +	xe->info.probe_display = false;
>  	unset_display_features(xe);
>  	return 0;
>  }
> diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
> index 1aba6f9eaa19..206328387150 100644
> --- a/drivers/gpu/drm/xe/xe_device.c
> +++ b/drivers/gpu/drm/xe/xe_device.c
> @@ -543,7 +543,7 @@ static void update_device_info(struct xe_device *xe)
>  {
>  	/* disable features that are not available/applicable to VFs */
>  	if (IS_SRIOV_VF(xe)) {
> -		xe->info.enable_display = 0;
> +		xe->info.probe_display = 0;
>  		xe->info.has_heci_gscfi = 0;
>  		xe->info.skip_guc_pc = 1;
>  		xe->info.skip_pcode = 1;
> diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
> index 5b7292a9a66d..82e99a3e084e 100644
> --- a/drivers/gpu/drm/xe/xe_device_types.h
> +++ b/drivers/gpu/drm/xe/xe_device_types.h
> @@ -282,8 +282,11 @@ struct xe_device {
>  		u8 has_sriov:1;
>  		/** @info.has_usm: Device has unified shared memory support */
>  		u8 has_usm:1;
> -		/** @info.enable_display: display enabled */
> -		u8 enable_display:1;
> +		/**
> +		 * @info.probe_display: probe display HW, otherwise it's left
> +		 * untouched in whatever state the firmware left it
> +		 */
> +		u8 probe_display:1;
>  		/** @info.skip_mtcfg: skip Multi-Tile configuration from MTCFG register */
>  		u8 skip_mtcfg:1;
>  		/** @info.skip_pcode: skip access to PCODE uC */
> diff --git a/drivers/gpu/drm/xe/xe_module.c b/drivers/gpu/drm/xe/xe_module.c
> index 7bb99e451fcc..923460119cec 100644
> --- a/drivers/gpu/drm/xe/xe_module.c
> +++ b/drivers/gpu/drm/xe/xe_module.c
> @@ -15,7 +15,7 @@
>  #include "xe_sched_job.h"
>  
>  struct xe_modparam xe_modparam = {
> -	.enable_display = true,
> +	.probe_display = true,
>  	.guc_log_level = 5,
>  	.force_probe = CONFIG_DRM_XE_FORCE_PROBE,
>  #ifdef CONFIG_PCI_IOV
> @@ -28,8 +28,8 @@ struct xe_modparam xe_modparam = {
>  module_param_named_unsafe(force_execlist, xe_modparam.force_execlist, bool, 0444);
>  MODULE_PARM_DESC(force_execlist, "Force Execlist submission");
>  
> -module_param_named(enable_display, xe_modparam.enable_display, bool, 0444);
> -MODULE_PARM_DESC(enable_display, "Enable display");
> +module_param_named(probe_display, xe_modparam.probe_display, bool, 0444);
> +MODULE_PARM_DESC(probe_display, "Probe display HW, otherwise it's left untouched (default: true)");
>  
>  module_param_named(vram_bar_size, xe_modparam.force_vram_bar_size, uint, 0600);
>  MODULE_PARM_DESC(vram_bar_size, "Set the vram bar size(in MiB)");
> diff --git a/drivers/gpu/drm/xe/xe_module.h b/drivers/gpu/drm/xe/xe_module.h
> index 61a0d28a28c8..161a5e6f717f 100644
> --- a/drivers/gpu/drm/xe/xe_module.h
> +++ b/drivers/gpu/drm/xe/xe_module.h
> @@ -11,7 +11,7 @@
>  /* Module modprobe variables */
>  struct xe_modparam {
>  	bool force_execlist;
> -	bool enable_display;
> +	bool probe_display;
>  	u32 force_vram_bar_size;
>  	int guc_log_level;
>  	char *guc_firmware_path;
> diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
> index f818aa69f3ca..b304855624ce 100644
> --- a/drivers/gpu/drm/xe/xe_pci.c
> +++ b/drivers/gpu/drm/xe/xe_pci.c
> @@ -621,9 +621,9 @@ static int xe_info_init_early(struct xe_device *xe,
>  	xe->info.skip_mtcfg = desc->skip_mtcfg;
>  	xe->info.skip_pcode = desc->skip_pcode;
>  
> -	xe->info.enable_display = IS_ENABLED(CONFIG_DRM_XE_DISPLAY) &&
> -				  xe_modparam.enable_display &&
> -				  desc->has_display;
> +	xe->info.probe_display = IS_ENABLED(CONFIG_DRM_XE_DISPLAY) &&
> +				 xe_modparam.probe_display &&
> +				 desc->has_display;
>  
>  	err = xe_tile_init_early(xe_device_get_root_tile(xe), xe, 0);
>  	if (err)
> @@ -834,7 +834,7 @@ static int xe_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>  		xe->info.media_name,
>  		xe->info.media_verx100 / 100,
>  		xe->info.media_verx100 % 100,
> -		str_yes_no(xe->info.enable_display),
> +		str_yes_no(xe->info.probe_display),
>  		xe->info.dma_mask_size, xe->info.tile_count,
>  		xe->info.has_heci_gscfi, xe->info.has_heci_cscfi);

-- 
Jani Nikula, Intel