From 9343bb247bf892f7d8731da107dc9d317834bbef Mon Sep 17 00:00:00 2001 From: Matt Roper Date: Tue, 11 Dec 2018 09:31:06 -0800 Subject: [PATCH] drm/i915: Don't use DDB allocation when choosing gen9 watermark method MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The bspec gives an if/else chain for choosing whether to use "method 1" or "method 2" for calculating the watermark "Selected Result Blocks" value for a plane. One of the branches of the if chain is: "Else If ('plane buffer allocation' is known and (plane buffer allocation / plane blocks per line) >=1)" Since our driver currently calculates DDB allocations first and the actual watermark values second, the plane buffer allocation is known at this point in our code and we include this test in our driver's logic. However we plan to soon move to a "watermarks first, ddb allocation second" sequence where we won't know the DDB allocation at this point. Let's drop this arm of the if/else statement (effectively considering the DDB allocation unknown) as an independent patch so that any regressions can be more accurately bisected to either the different watermark value (in this patch) or the new DDB allocation (in the next patch). Signed-off-by: Matt Roper Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20181211173107.11068-1-matthew.d.roper@intel.com --- drivers/gpu/drm/i915/intel_pm.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 2bba5315b764..bf970cf7b8a5 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -4761,13 +4761,6 @@ static int skl_compute_plane_wm(const struct intel_crtc_state *cstate, wp->dbuf_block_size < 1) && (wp->plane_bytes_per_line / wp->dbuf_block_size < 1)) { selected_result = method2; - } else if (ddb_allocation >= - fixed16_to_u32_round_up(wp->plane_blocks_per_line)) { - if (IS_GEN9(dev_priv) && - !IS_GEMINILAKE(dev_priv)) - selected_result = min_fixed16(method1, method2); - else - selected_result = method2; } else if (latency >= wp->linetime_us) { if (IS_GEN9(dev_priv) && !IS_GEMINILAKE(dev_priv)) -- 2.30.2