From patchwork Mon Mar 13 09:29:30 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jyri Sarha X-Patchwork-Id: 9620375 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7455E60414 for ; Mon, 13 Mar 2017 09:29:47 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6432828458 for ; Mon, 13 Mar 2017 09:29:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 58D812845E; Mon, 13 Mar 2017 09:29:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 3ABE028458 for ; Mon, 13 Mar 2017 09:29:46 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A8DFC6E3C2; Mon, 13 Mar 2017 09:29:45 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from lelnx194.ext.ti.com (lelnx194.ext.ti.com [198.47.27.80]) by gabe.freedesktop.org (Postfix) with ESMTPS id 941166E3C2 for ; Mon, 13 Mar 2017 09:29:43 +0000 (UTC) Received: from dlelxv90.itg.ti.com ([172.17.2.17]) by lelnx194.ext.ti.com (8.15.1/8.15.1) with ESMTP id v2D9TaGA005401; Mon, 13 Mar 2017 04:29:36 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ti.com; s=ti-com-17Q1; t=1489397376; bh=6srqkvGvI22GxeKzbvBIRpQfSciBQjgUONFOh/odP0Q=; h=From:To:CC:Subject:Date; b=qUKt5VKAH9zfd6j3eKoOS/tql7leUaCZSVmFnDgfmqSRzxg9QkLRVIQ1aHSyP4nLn /qklrsXO6+brsPdW7K57HtHnh7/VlZpnEMxEzDH4uFFwaA8RTTiSQzbRnwIWZWfj6D kVqT8qlL08cwkGVPavlMVLF1frbogDroMeAyx83s= Received: from DFLE72.ent.ti.com (dfle72.ent.ti.com [128.247.5.109]) by dlelxv90.itg.ti.com (8.14.3/8.13.8) with ESMTP id v2D9TZSq012207; Mon, 13 Mar 2017 04:29:35 -0500 Received: from dflp32.itg.ti.com (10.64.6.15) by DFLE72.ent.ti.com (128.247.5.109) with Microsoft SMTP Server id 14.3.294.0; Mon, 13 Mar 2017 04:29:35 -0500 Received: from jadmar.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by dflp32.itg.ti.com (8.14.3/8.13.8) with ESMTP id v2D9TWC0024157; Mon, 13 Mar 2017 04:29:33 -0500 From: Jyri Sarha To: , Subject: [PATCH v2] drm/tilcdc: Set framebuffer DMA address to HW only if CRTC is enabled Date: Mon, 13 Mar 2017 11:29:30 +0200 Message-ID: <1489397370-7640-1-git-send-email-jsarha@ti.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 Cc: khilman@baylibre.com, Jyri Sarha , tomi.valkeinen@ti.com, laurent.pinchart@ideasonboard.com X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP Touching HW while clocks are off is a serious error and for instance breaks suspend functionality. After this patch tilcdc_crtc_update_fb() always updates the primary plane's framebuffer pointer, increases fb's reference count and stores vblank event. tilcdc_crtc_update_fb() only writes the fb's DMA address to HW if the crtc is enabled, as tilcdc_crtc_enable() takes care of writing the address on enable. This patch also refactors the tilcdc_crtc_update_fb() a bit. Number of subsequent small changes had made it almost unreadable. There should be no other functional changes but checking the CRTC's enable state. However, the locking goes a bit differently and some of the redundant checks have been removed in this new version. The enable_lock should be enough to protect the access to tilcdc_crtc->enabled. The irq_lock protects the access to last_vblank and next_fb. The check for vrefresh and last_vblank being valid is redundant, as the vrefresh should be always valid if the CRTC is enabled and now last_vblank should be too, because it is initialized to current time when CRTC raster is enabled. If for some reason the values are not correctly initialized the division by zero warning is quite appropriate. Signed-off-by: Jyri Sarha Reviewed-by: Tomi Valkeinen --- Since first version: - Restored the accidentally removed comment begin mark to beginning of file - Fixed two typos and one broken sentence, pointed out by Tomi Valkeinen drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 35 +++++++++++++++++++++++------------ 1 file changed, 23 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c index f80bf93..f2a16fa 100644 --- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c +++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c @@ -464,6 +464,7 @@ static void tilcdc_crtc_enable(struct drm_crtc *crtc) { struct drm_device *dev = crtc->dev; struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc); + unsigned long flags; WARN_ON(!drm_modeset_is_locked(&crtc->mutex)); mutex_lock(&tilcdc_crtc->enable_lock); @@ -484,7 +485,17 @@ static void tilcdc_crtc_enable(struct drm_crtc *crtc) tilcdc_write_mask(dev, LCDC_RASTER_CTRL_REG, LCDC_PALETTE_LOAD_MODE(DATA_ONLY), LCDC_PALETTE_LOAD_MODE_MASK); + + /* There is no real chance for a race here as the time stamp + * is taken before the raster DMA is started. The spin-lock is + * taken to have a memory barrier after taking the time-stamp + * and to avoid a context switch between taking the stamp and + * enabling the raster. + */ + spin_lock_irqsave(&tilcdc_crtc->irq_lock, flags); + tilcdc_crtc->last_vblank = ktime_get(); tilcdc_set(dev, LCDC_RASTER_CTRL_REG, LCDC_RASTER_ENABLE); + spin_unlock_irqrestore(&tilcdc_crtc->irq_lock, flags); drm_crtc_vblank_on(crtc); @@ -539,7 +550,6 @@ static void tilcdc_crtc_off(struct drm_crtc *crtc, bool shutdown) } drm_flip_work_commit(&tilcdc_crtc->unref_work, priv->wq); - tilcdc_crtc->last_vblank = 0; tilcdc_crtc->enabled = false; mutex_unlock(&tilcdc_crtc->enable_lock); @@ -602,7 +612,6 @@ int tilcdc_crtc_update_fb(struct drm_crtc *crtc, { struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc); struct drm_device *dev = crtc->dev; - unsigned long flags; WARN_ON(!drm_modeset_is_locked(&crtc->mutex)); @@ -614,28 +623,30 @@ int tilcdc_crtc_update_fb(struct drm_crtc *crtc, drm_framebuffer_reference(fb); crtc->primary->fb = fb; + tilcdc_crtc->event = event; - spin_lock_irqsave(&tilcdc_crtc->irq_lock, flags); + mutex_lock(&tilcdc_crtc->enable_lock); - if (crtc->hwmode.vrefresh && ktime_to_ns(tilcdc_crtc->last_vblank)) { + if (tilcdc_crtc->enabled) { + unsigned long flags; ktime_t next_vblank; s64 tdiff; + spin_lock_irqsave(&tilcdc_crtc->irq_lock, flags); + next_vblank = ktime_add_us(tilcdc_crtc->last_vblank, - 1000000 / crtc->hwmode.vrefresh); - + 1000000 / crtc->hwmode.vrefresh); tdiff = ktime_to_us(ktime_sub(next_vblank, ktime_get())); if (tdiff < TILCDC_VBLANK_SAFETY_THRESHOLD_US) tilcdc_crtc->next_fb = fb; + else + set_scanout(crtc, fb); + + spin_unlock_irqrestore(&tilcdc_crtc->irq_lock, flags); } - if (tilcdc_crtc->next_fb != fb) - set_scanout(crtc, fb); - - tilcdc_crtc->event = event; - - spin_unlock_irqrestore(&tilcdc_crtc->irq_lock, flags); + mutex_unlock(&tilcdc_crtc->enable_lock); return 0; }