[Intel-gfx] [PATCH] drm/i915: do not read swizzle info if unavailable

[Chris Wilson]

Quoting Lucas De Marchi (2020-07-01 19:36:26)
> Since gen8 we don't use swizzle anymore. Don't dump registers related to
> it: registers may or may not be there.
> 
> Cc: Matt Roper <matthew.d.roper at intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_debugfs.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 8594a8ef08ce..d9e56eee0453 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -1138,13 +1138,17 @@ static int i915_swizzle_info(struct seq_file *m, void *data)
>         struct intel_uncore *uncore = &dev_priv->uncore;
>         intel_wakeref_t wakeref;
>  
> -       wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
> -
>         seq_printf(m, "bit6 swizzle for X-tiling = %s\n",
>                    swizzle_string(dev_priv->ggtt.bit_6_swizzle_x));
>         seq_printf(m, "bit6 swizzle for Y-tiling = %s\n",
>                    swizzle_string(dev_priv->ggtt.bit_6_swizzle_y));

I'm really tempted to say kill this, it's past the point of usefulness.
There's one user in igt, who can just use the information provided via
the get_tiling_ioctl.

However, if you pull the

        if (dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES)
                seq_puts(m, "L-shaped memory detected\n");

here to before the register read out as well (as that is also plain
driver state), you have a deal.
-Chris