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

[Shankar, Uma]

> -----Original Message-----
> From: Murthy, Arun R <arun.r.murthy at intel.com>
> Sent: Wednesday, October 4, 2023 12:13 PM
> To: Shankar, Uma <uma.shankar at intel.com>; intel-gfx at lists.freedesktop.org
> Cc: Nikula, Jani <jani.nikula at intel.com>
> Subject: RE: [Intel-gfx] [v4] drm/i915/display: Created exclusive version of vga
> decode setup
> 
> 
> > -----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 Arun, Ville and Jani for the reviews.
Pushed the change to drm-intel-next.

Will create a follow-up internal task for vga cleanup and handling as suggested by Ville.

Regards,
Uma Shankar

> 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