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

[Ander Conselvan de Oliveira]

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;
+
+	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