From e11ffddba1f363f9713442500f779693b0d7cc19 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Mon, 27 Mar 2017 21:55:46 +0300 Subject: [PATCH] drm/i915: Simplify cursor register write sequence MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit It looks like simply writing all the cursor register every single time might be slightly faster than checking to see of each of them need to be written. So if any other register apart from CURPOS needs to be written let's just write all the registers. CURPOS is left as a special case mainly for 845/865 where we have to disable the cursor to change many of the cursor parameters. This introduces a slight chance of the cursor flickering when things get updated (since we're not currently doing the vblank evade for cursor updates). If we write CURPOS alone then that obviously can't happen. And let's follow the same pattern in the i9xx code just for symmetry. I wasn't able to see a singificant performance difference between this and just writing all the registers unconditionally. Signed-off-by: Ville Syrjälä Link: http://patchwork.freedesktop.org/patch/msgid/20170327185546.2977-16-ville.syrjala@linux.intel.com Reviewed-by: Imre Deak --- drivers/gpu/drm/i915/intel_display.c | 69 ++++++++++++++-------------- 1 file changed, 34 insertions(+), 35 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index fa951701c8cf..2256cf096e58 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -9332,36 +9332,28 @@ static void i845_update_cursor(struct intel_plane *plane, spin_lock_irqsave(&dev_priv->uncore.lock, irqflags); - if (plane->cursor.cntl != 0 && - (plane->cursor.base != base || - plane->cursor.size != size || - plane->cursor.cntl != cntl)) { - /* On these chipsets we can only modify the base/size/stride - * whilst the cursor is disabled. - */ + /* On these chipsets we can only modify the base/size/stride + * whilst the cursor is disabled. + */ + if (plane->cursor.base != base || + plane->cursor.size != size || + plane->cursor.cntl != cntl) { I915_WRITE_FW(CURCNTR(PIPE_A), 0); - plane->cursor.cntl = 0; - } - - if (plane->cursor.base != base) I915_WRITE_FW(CURBASE(PIPE_A), base); - - if (plane->cursor.size != size) I915_WRITE_FW(CURSIZE, size); - - if (cntl) I915_WRITE_FW(CURPOS(PIPE_A), pos); - - if (plane->cursor.cntl != cntl) I915_WRITE_FW(CURCNTR(PIPE_A), cntl); + plane->cursor.base = base; + plane->cursor.size = size; + plane->cursor.cntl = cntl; + } else { + I915_WRITE_FW(CURPOS(PIPE_A), pos); + } + POSTING_READ_FW(CURCNTR(PIPE_A)); spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags); - - plane->cursor.cntl = cntl; - plane->cursor.base = base; - plane->cursor.size = size; } static void i845_disable_cursor(struct intel_plane *plane, @@ -9517,27 +9509,34 @@ static void i9xx_update_cursor(struct intel_plane *plane, spin_lock_irqsave(&dev_priv->uncore.lock, irqflags); - if (plane->cursor.cntl != cntl) + /* + * On some platforms writing CURCNTR first will also + * cause CURPOS to be armed by the CURBASE write. + * Without the CURCNTR write the CURPOS write would + * arm itself. + * + * CURCNTR and CUR_FBC_CTL are always + * armed by the CURBASE write only. + */ + if (plane->cursor.base != base || + plane->cursor.size != fbc_ctl || + plane->cursor.cntl != cntl) { I915_WRITE_FW(CURCNTR(pipe), cntl); - - if (plane->cursor.size != fbc_ctl) - I915_WRITE_FW(CUR_FBC_CTL(pipe), fbc_ctl); - - if (cntl) + if (HAS_CUR_FBC(dev_priv)) + I915_WRITE_FW(CUR_FBC_CTL(pipe), fbc_ctl); I915_WRITE_FW(CURPOS(pipe), pos); - - if (plane->cursor.cntl != cntl || - plane->cursor.size != fbc_ctl || - plane->cursor.base != base) I915_WRITE_FW(CURBASE(pipe), base); + plane->cursor.base = base; + plane->cursor.size = fbc_ctl; + plane->cursor.cntl = cntl; + } else { + I915_WRITE_FW(CURPOS(pipe), pos); + } + POSTING_READ_FW(CURBASE(pipe)); spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags); - - plane->cursor.cntl = cntl; - plane->cursor.base = base; - plane->cursor.size = fbc_ctl; } static void i9xx_disable_cursor(struct intel_plane *plane, -- 2.30.2