[Intel-gfx] [v4] drm/i915/display: Created exclusive version of vga decode setup

[Murthy, Arun R]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Uma
> Shankar
> Sent: Friday, September 29, 2023 1:13 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: Nikula, Jani <jani.nikula at intel.com>
> Subject: [Intel-gfx] [v4] drm/i915/display: Created exclusive version of vga
> decode setup
> 
> Current vga arbiter implementation in i915 needs a re-design.
> The current approach would cause real problems if anyone actually needs to
> talk another GPU using legacy VGA resources.
> 
> The main issue is that X becomes a slideshow if it thinks there are multiple
> GPUs that have VGA decoding enabled as it insists on adjusting the VGA routing
> pretty much for every little operation involving any of the GPUs.
> 
> The cleanup will be planned for i915. Meanwhile to focus on Xe upstreaming
> and have a cleaner separation, the said functionality is being moved to a
> different file exclusive for i915. Xe driver will re-use rest of the display code
> from i915.
> 
> v2: Addressed Jani Nikula's review comments.
> 
> v3: Dropped a duplicate function (Jani)
> 
> v4: Updated commit message with reasoning as sugested by Ville.
> 
> Signed-off-by: Uma Shankar <uma.shankar at intel.com>

Reviewed-by: Arun R Murthy <arun.r.murthy at intel.com>

Thanks and Regards,
Arun R Murthy
--------------------
> ---
>  drivers/gpu/drm/i915/display/intel_vga.c | 18 +-----------------
>  drivers/gpu/drm/i915/soc/intel_gmch.c    | 14 ++++++++++++++
>  drivers/gpu/drm/i915/soc/intel_gmch.h    |  2 ++
>  3 files changed, 17 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_vga.c
> b/drivers/gpu/drm/i915/display/intel_vga.c
> index 286a0bdd28c6..4b98833bfa8c 100644
> --- a/drivers/gpu/drm/i915/display/intel_vga.c
> +++ b/drivers/gpu/drm/i915/display/intel_vga.c
> @@ -3,11 +3,9 @@
>   * Copyright © 2019 Intel Corporation
>   */
> 
> -#include <linux/pci.h>
>  #include <linux/vgaarb.h>
> 
>  #include <video/vga.h>
> -
>  #include "soc/intel_gmch.h"
> 
>  #include "i915_drv.h"
> @@ -99,20 +97,6 @@ void intel_vga_reset_io_mem(struct drm_i915_private
> *i915)
>  	vga_put(pdev, VGA_RSRC_LEGACY_IO);
>  }
> 
> -static unsigned int
> -intel_vga_set_decode(struct pci_dev *pdev, bool enable_decode) -{
> -	struct drm_i915_private *i915 = pdev_to_i915(pdev);
> -
> -	intel_gmch_vga_set_state(i915, enable_decode);
> -
> -	if (enable_decode)
> -		return VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
> -		       VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
> -	else
> -		return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
> -}
> -
>  int intel_vga_register(struct drm_i915_private *i915)  {
> 
> @@ -127,7 +111,7 @@ int intel_vga_register(struct drm_i915_private *i915)
>  	 * then we do not take part in VGA arbitration and the
>  	 * vga_client_register() fails with -ENODEV.
>  	 */
> -	ret = vga_client_register(pdev, intel_vga_set_decode);
> +	ret = vga_client_register(pdev, intel_gmch_vga_set_decode);
>  	if (ret && ret != -ENODEV)
>  		return ret;
> 
> diff --git a/drivers/gpu/drm/i915/soc/intel_gmch.c
> b/drivers/gpu/drm/i915/soc/intel_gmch.c
> index 49c7fb16e934..f32e9f78770a 100644
> --- a/drivers/gpu/drm/i915/soc/intel_gmch.c
> +++ b/drivers/gpu/drm/i915/soc/intel_gmch.c
> @@ -5,6 +5,7 @@
> 
>  #include <linux/pci.h>
>  #include <linux/pnp.h>
> +#include <linux/vgaarb.h>
> 
>  #include <drm/drm_managed.h>
>  #include <drm/i915_drm.h>
> @@ -167,3 +168,16 @@ int intel_gmch_vga_set_state(struct
> drm_i915_private *i915, bool enable_decode)
> 
>  	return 0;
>  }
> +
> +unsigned int intel_gmch_vga_set_decode(struct pci_dev *pdev, bool
> +enable_decode) {
> +	struct drm_i915_private *i915 = pdev_to_i915(pdev);
> +
> +	intel_gmch_vga_set_state(i915, enable_decode);
> +
> +	if (enable_decode)
> +		return VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
> +		       VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
> +	else
> +		return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; }
> diff --git a/drivers/gpu/drm/i915/soc/intel_gmch.h
> b/drivers/gpu/drm/i915/soc/intel_gmch.h
> index d0133eedc720..23be2d113afd 100644
> --- a/drivers/gpu/drm/i915/soc/intel_gmch.h
> +++ b/drivers/gpu/drm/i915/soc/intel_gmch.h
> @@ -8,11 +8,13 @@
> 
>  #include <linux/types.h>
> 
> +struct pci_dev;
>  struct drm_i915_private;
> 
>  int intel_gmch_bridge_setup(struct drm_i915_private *i915);  void
> intel_gmch_bar_setup(struct drm_i915_private *i915);  void
> intel_gmch_bar_teardown(struct drm_i915_private *i915);  int
> intel_gmch_vga_set_state(struct drm_i915_private *i915, bool enable_decode);
> +unsigned int intel_gmch_vga_set_decode(struct pci_dev *pdev, bool
> +enable_decode);
> 
>  #endif /* __INTEL_GMCH_H__ */
> --
> 2.42.0