Re: [Intel-gfx] [PATCH v2 02/23] drm/i915: Add DISPLAY_VER()

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

On Thu, 11 Mar 2021, Matt Roper <matthew.d.roper@intel.com> wrote:
> Although we've long referred to platforms by a single "GEN" number, the
> hardware teams have recommended that we stop doing this since the
> various component IP blocks are going to start using independent number
> schemes with varying cadence.  To support this, hardware platforms a bit
> down the road are going to start providing MMIO registers that the
> driver can read to obtain the "graphics version," "media version," and
> "display version" without needing to do a PCI ID -> platform -> version
> translation.
>
> Although our current platforms don't yet expose these registers (and the
> next couple we release probably won't have them yet either), the
> hardware teams would still like to see us move to this independent
> numbering scheme now in preparation.  For i915 that means we should try
> to eliminate all usage of INTEL_GEN() throughout our code and instead
> replace it with separate GRAPHICS_VER(), MEDIA_VER(), and DISPLAY_VER()
> constructs in the code.  For old platforms, these will all usually give
> the same value for each IP block (aside from a few special cases like
> GLK which we can no more accurately represent as graphics=9 +
> display=10), but future platforms will have more flexibility to bump IP
> version numbers independently.
>
> The next hardware platform we'll be upstreaming (very soon!) will have a
> display version of 13 and a graphics version of 12, so let's just the
> first step of breaking out DISPLAY_VER(), but leaving the rest of
> INTEL_GEN() untouched for now.  For now we'll automatically
> derive the display version from the platform's INTEL_GEN() value except
> in cases where an alternative display version is explicitly provided in
> the device info structure.
>
> Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h          | 2 ++
>  drivers/gpu/drm/i915/i915_pci.c          | 2 +-
>  drivers/gpu/drm/i915/intel_device_info.h | 3 +++
>  3 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 4fe90a9782e8..5ec0524d3418 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1247,6 +1247,8 @@ static inline struct drm_i915_private *pdev_to_i915(struct pci_dev *pdev)
>  #define INTEL_GEN(dev_priv)	(INTEL_INFO(dev_priv)->gen)
>  #define INTEL_DEVID(dev_priv)	(RUNTIME_INFO(dev_priv)->device_id)
>  
> +#define DISPLAY_VER(i915)	INTEL_INFO(i915)->display_ver

The value needs to be wrapped in parenthesis.

Maybe this should be ->display.version?

> +
>  #define REVID_FOREVER		0xff
>  #define INTEL_REVID(dev_priv)	(to_pci_dev((dev_priv)->drm.dev)->revision)
>  
> diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
> index a9f24f2bda33..3543611cf0fc 100644
> --- a/drivers/gpu/drm/i915/i915_pci.c
> +++ b/drivers/gpu/drm/i915/i915_pci.c
> @@ -36,7 +36,7 @@
>  #include "i915_selftest.h"
>  
>  #define PLATFORM(x) .platform = (x)
> -#define GEN(x) .gen = (x), .gen_mask = BIT((x) - 1)
> +#define GEN(x) .gen = (x), .gen_mask = BIT((x) - 1), .display_ver = x

x needs parenthesis.

>  
>  #define I845_PIPE_OFFSETS \
>  	.pipe_offsets = { \
> diff --git a/drivers/gpu/drm/i915/intel_device_info.h b/drivers/gpu/drm/i915/intel_device_info.h
> index d44f64b57b7a..3c7db9c690f4 100644
> --- a/drivers/gpu/drm/i915/intel_device_info.h
> +++ b/drivers/gpu/drm/i915/intel_device_info.h
> @@ -162,6 +162,9 @@ struct intel_device_info {
>  
>  	u8 gen;
>  	u8 gt; /* GT number, 0 if undefined */
> +
> +	u8 display_ver;
> +
>  	intel_engine_mask_t platform_engine_mask; /* Engines supported by the HW */
>  
>  	enum intel_platform platform;

-- 
Jani Nikula, Intel Open Source Graphics Center
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