[Intel-gfx] [PATCH v2 2/4] drm/i915/glk: Fix maximum scaling factor for Geminilake scalers

[Ville Syrjälä]

On Thu, Feb 23, 2017 at 09:15:58AM +0200, Ander Conselvan de Oliveira wrote:
> Geminilake can output two pixels per clock, and that affects the maximum
> scaling factor for its scalers. Take that into account and avoid the
> following warning:
> 
> WARNING: CPU: 1 PID: 593 at drivers/gpu/drm/i915/intel_display.c:13223 skl_max_scale.part.129+0x78/0x80 [i915]
> WARN_ON_ONCE(!crtc_clock || cdclk < crtc_clock)
> Modules linked in: x86_pkg_temp_thermal i915 coretemp kvm_intel kvm i2c_algo_bit drm_kms_helper irqbypass crct10dif_pclmul prime_numbers crc32_pclmul drm ghash_clmulni_intel shpchp tpm_tis tpm_tis_core tpm nfsd authw
> CPU: 1 PID: 593 Comm: kworker/u8:3 Tainted: G        W       4.10.0-rc8ander+ #330
> Hardware name: Intel Corp. Geminilake/GLK RVP1 DDR4 (05), BIOS GELKRVPA.X64.0035.B33.1702150552 02/15/2017
> Workqueue: events_unbound async_run_entry_fn
> Call Trace:
>  dump_stack+0x86/0xc3
>  __warn+0xcb/0xf0
>  warn_slowpath_fmt+0x5f/0x80
>  skl_max_scale.part.129+0x78/0x80 [i915]
>  intel_check_primary_plane+0xa6/0xc0 [i915]
>  intel_plane_atomic_check_with_state+0xd1/0x1a0 [i915]
>  ? drm_printk+0xb5/0xc0 [drm]
>  intel_plane_atomic_check+0x3d/0x80 [i915]
>  drm_atomic_helper_check_planes+0x7c/0x200 [drm_kms_helper]
>  intel_atomic_check+0xa5b/0x11a0 [i915]
>  drm_atomic_check_only+0x353/0x600 [drm]
>  ? drm_atomic_add_affected_connectors+0x10c/0x120 [drm]
>  drm_atomic_commit+0x18/0x50 [drm]
>  restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper]
>  drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper]
>  drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper]
>  intel_fbdev_set_par+0x1a/0x70 [i915]
>  fbcon_init+0x582/0x610
>  visual_init+0xd6/0x130
>  do_bind_con_driver+0x1da/0x3c0
>  do_take_over_console+0x116/0x180
>  do_fbcon_takeover+0x5c/0xb0
>  fbcon_event_notify+0x772/0x8a0
>  ? __blocking_notifier_call_chain+0x35/0x70
>  notifier_call_chain+0x4a/0x70
>  __blocking_notifier_call_chain+0x4d/0x70
>  blocking_notifier_call_chain+0x16/0x20
>  fb_notifier_call_chain+0x1b/0x20
>  register_framebuffer+0x278/0x360
>  drm_fb_helper_initial_config+0x253/0x440 [drm_kms_helper]
>  intel_fbdev_initial_config+0x18/0x30 [i915]
>  async_run_entry_fn+0x39/0x170
>  process_one_work+0x212/0x670
>  ? process_one_work+0x197/0x670
>  worker_thread+0x4e/0x490
>  kthread+0x101/0x140
>  ? process_one_work+0x670/0x670
>  ? kthread_create_on_node+0x60/0x60
>  ret_from_fork+0x31/0x40
> 
> v2: s/max_pixclk/max_dotclk/ (Ville)
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 957c62d..6b65adf 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -13211,16 +13211,22 @@ intel_cleanup_plane_fb(struct drm_plane *plane,
>  int
>  skl_max_scale(struct intel_crtc *intel_crtc, struct intel_crtc_state *crtc_state)
>  {
> +	struct drm_i915_private *dev_priv;
>  	int max_scale;
> -	int crtc_clock, cdclk;
> +	int crtc_clock, max_dotclk;
>  
>  	if (!intel_crtc || !crtc_state->base.enable)
>  		return DRM_PLANE_HELPER_NO_SCALING;
>  
> +	dev_priv = to_i915(intel_crtc->base.dev);
> +
>  	crtc_clock = crtc_state->base.adjusted_mode.crtc_clock;
> -	cdclk = to_intel_atomic_state(crtc_state->base.state)->cdclk.logical.cdclk;
> +	max_dotclk = to_intel_atomic_state(crtc_state->base.state)->cdclk.logical.cdclk;

I actually meant using dev_priv->max_dotclock (or whatever it was
called). But now that I actually read the code I see that it wouldn't
work. So this looks fine

Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

> +
> +	if (IS_GEMINILAKE(dev_priv))
> +		max_dotclk *= 2;
>  
> -	if (WARN_ON_ONCE(!crtc_clock || cdclk < crtc_clock))
> +	if (WARN_ON_ONCE(!crtc_clock || max_dotclk < crtc_clock))
>  		return DRM_PLANE_HELPER_NO_SCALING;
>  
>  	/*
> @@ -13229,7 +13235,8 @@ skl_max_scale(struct intel_crtc *intel_crtc, struct intel_crtc_state *crtc_state
>  	 *            or
>  	 *    cdclk/crtc_clock
>  	 */
> -	max_scale = min((1 << 16) * 3 - 1, (1 << 8) * ((cdclk << 8) / crtc_clock));
> +	max_scale = min((1 << 16) * 3 - 1,
> +			(1 << 8) * ((max_dotclk << 8) / crtc_clock));
>  
>  	return max_scale;
>  }
> -- 
> 2.9.3

-- 
Ville Syrjälä
Intel OTC