From patchwork Tue Oct 21 10:58:13 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dheeraj Jamwal X-Patchwork-Id: 5122251 Return-Path: X-Original-To: patchwork-ltsi-dev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 5F2BA9F349 for ; Tue, 21 Oct 2014 12:07:35 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E38E920148 for ; Tue, 21 Oct 2014 12:07:33 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EC58C20121 for ; Tue, 21 Oct 2014 12:07:31 +0000 (UTC) Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 6EB381457; Tue, 21 Oct 2014 11:14:16 +0000 (UTC) X-Original-To: ltsi-dev@lists.linuxfoundation.org Delivered-To: ltsi-dev@mail.linuxfoundation.org Received: from smtp2.linuxfoundation.org (smtp2.linux-foundation.org [172.17.192.36]) by mail.linuxfoundation.org (Postfix) with ESMTPS id DC73CA04 for ; Tue, 21 Oct 2014 11:14:14 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by smtp2.linuxfoundation.org (Postfix) with ESMTP id 0E4E91DCCA for ; Tue, 21 Oct 2014 11:14:12 +0000 (UTC) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP; 21 Oct 2014 04:14:11 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,761,1406617200"; d="scan'208";a="617800883" Received: from ubuntu-desktop.png.intel.com ([10.221.122.25]) by fmsmga002.fm.intel.com with ESMTP; 21 Oct 2014 04:14:09 -0700 From: Dheeraj Jamwal To: ltsi-dev@lists.linuxfoundation.org Date: Tue, 21 Oct 2014 18:58:13 +0800 Message-Id: <1413889294-31328-894-git-send-email-dheerajx.s.jamwal@intel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> References: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> MIME-Version: 1.0 X-Spam-Status: No, score=-5.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org Subject: [LTSI-dev] [PATCH 0893/1094] drm/irq: kerneldoc polish X-BeenThere: ltsi-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: "A list to discuss patches, development, and other things related to the LTSI project" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: ltsi-dev-bounces@lists.linuxfoundation.org Errors-To: ltsi-dev-bounces@lists.linuxfoundation.org X-Virus-Scanned: ClamAV using ClamSMTP From: Daniel Vetter - Integrate into the drm DocBook - Disable kerneldoc for functions not exported to drivers. - Properly document the new drm_vblank_on|off and add cautious comments explaining when drm_vblank_pre|post_modesets shouldn't be used. - General polish and OCD. v2: Polish as suggested by Thierry. Cc: Thierry Reding Reviewed-by: Ville Syrjälä Signed-off-by: Daniel Vetter (cherry picked from commit f5752b38970990fa1495839751aed64bd178b9e0) Signed-off-by: Dheeraj Jamwal --- Documentation/DocBook/drm.tmpl | 5 +- drivers/gpu/drm/drm_irq.c | 165 ++++++++++++++++++++++++++++------------ 2 files changed, 121 insertions(+), 49 deletions(-) diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl index f4028c3..0287792 100644 --- a/Documentation/DocBook/drm.tmpl +++ b/Documentation/DocBook/drm.tmpl @@ -2519,6 +2519,10 @@ void (*disable_vblank) (struct drm_device *dev, int crtc); with a call to drm_vblank_cleanup in the driver unload operation handler. + + Vertical Blanking and Interrupt Handling Functions Reference +!Edrivers/gpu/drm/drm_irq.c + @@ -2871,7 +2875,6 @@ int num_ioctls; - diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index dd786d8..f3dafcc 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -1,6 +1,5 @@ -/** - * \file drm_irq.c - * IRQ support +/* + * drm_irq.c IRQ and vblank support * * \author Rickard E. (Rik) Faith * \author Gareth Hughes @@ -156,6 +155,12 @@ static void vblank_disable_fn(unsigned long arg) spin_unlock_irqrestore(&dev->vbl_lock, irqflags); } +/** + * drm_vblank_cleanup - cleanup vblank support + * @dev: DRM device + * + * This function cleans up any resources allocated in drm_vblank_init. + */ void drm_vblank_cleanup(struct drm_device *dev) { int crtc; @@ -175,6 +180,16 @@ void drm_vblank_cleanup(struct drm_device *dev) } EXPORT_SYMBOL(drm_vblank_cleanup); +/** + * drm_vblank_init - initialize vblank support + * @dev: drm_device + * @num_crtcs: number of crtcs supported by @dev + * + * This function initializes vblank support for @num_crtcs display pipelines. + * + * Returns: + * Zero on success or a negative error code on failure. + */ int drm_vblank_init(struct drm_device *dev, int num_crtcs) { int i, ret = -ENOMEM; @@ -238,13 +253,21 @@ static void drm_irq_vgaarb_nokms(void *cookie, bool state) } /** - * Install IRQ handler. - * - * \param dev DRM device. + * drm_irq_install - install IRQ handler + * @dev: DRM device + * @irq: IRQ number to install the handler for * * Initializes the IRQ related data. Installs the handler, calling the driver - * \c irq_preinstall() and \c irq_postinstall() functions - * before and after the installation. + * irq_preinstall() and irq_postinstall() functions before and after the + * installation. + * + * This is the simplified helper interface provided for drivers with no special + * needs. Drivers which need to install interrupt handlers for multiple + * interrupts must instead set drm_device->irq_enabled to signal the DRM core + * that vblank interrupts are available. + * + * Returns: + * Zero on success or a negative error code on failure. */ int drm_irq_install(struct drm_device *dev, int irq) { @@ -304,11 +327,20 @@ int drm_irq_install(struct drm_device *dev, int irq) EXPORT_SYMBOL(drm_irq_install); /** - * Uninstall the IRQ handler. + * drm_irq_uninstall - uninstall the IRQ handler + * @dev: DRM device + * + * Calls the driver's irq_uninstall() function and unregisters the IRQ handler. + * This should only be called by drivers which used drm_irq_install() to set up + * their interrupt handler. Other drivers must only reset + * drm_device->irq_enabled to false. * - * \param dev DRM device. + * Note that for kernel modesetting drivers it is a bug if this function fails. + * The sanity checks are only to catch buggy user modesetting drivers which call + * the same function through an ioctl. * - * Calls the driver's \c irq_uninstall() function, and stops the irq. + * Returns: + * Zero on success or a negative error code on failure. */ int drm_irq_uninstall(struct drm_device *dev) { @@ -353,7 +385,7 @@ int drm_irq_uninstall(struct drm_device *dev) } EXPORT_SYMBOL(drm_irq_uninstall); -/** +/* * IRQ control ioctl. * * \param inode device inode. @@ -406,15 +438,14 @@ int drm_control(struct drm_device *dev, void *data, } /** - * drm_calc_timestamping_constants - Calculate vblank timestamp constants - * - * @crtc drm_crtc whose timestamp constants should be updated. - * @mode display mode containing the scanout timings + * drm_calc_timestamping_constants - calculate vblank timestamp constants + * @crtc: drm_crtc whose timestamp constants should be updated. + * @mode: display mode containing the scanout timings * * Calculate and store various constants which are later * needed by vblank and swap-completion timestamping, e.g, * by drm_calc_vbltimestamp_from_scanoutpos(). They are - * derived from crtc's true scanout timing, so they take + * derived from CRTC's true scanout timing, so they take * things like panel scaling or other adjustments into account. */ void drm_calc_timestamping_constants(struct drm_crtc *crtc, @@ -459,11 +490,22 @@ void drm_calc_timestamping_constants(struct drm_crtc *crtc, EXPORT_SYMBOL(drm_calc_timestamping_constants); /** - * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms - * drivers. Implements calculation of exact vblank timestamps from - * given drm_display_mode timings and current video scanout position - * of a crtc. This can be called from within get_vblank_timestamp() - * implementation of a kms driver to implement the actual timestamping. + * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper + * @dev: DRM device + * @crtc: Which CRTC's vblank timestamp to retrieve + * @max_error: Desired maximum allowable error in timestamps (nanosecs) + * On return contains true maximum error of timestamp + * @vblank_time: Pointer to struct timeval which should receive the timestamp + * @flags: Flags to pass to driver: + * 0 = Default, + * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler + * @refcrtc: CRTC which defines scanout timing + * @mode: mode which defines the scanout timings + * + * Implements calculation of exact vblank timestamps from given drm_display_mode + * timings and current video scanout position of a CRTC. This can be called from + * within get_vblank_timestamp() implementation of a kms driver to implement the + * actual timestamping. * * Should return timestamps conforming to the OML_sync_control OpenML * extension specification. The timestamp corresponds to the end of @@ -478,21 +520,11 @@ EXPORT_SYMBOL(drm_calc_timestamping_constants); * returns as no operation if a doublescan or interlaced video mode is * active. Higher level code is expected to handle this. * - * @dev: DRM device. - * @crtc: Which crtc's vblank timestamp to retrieve. - * @max_error: Desired maximum allowable error in timestamps (nanosecs). - * On return contains true maximum error of timestamp. - * @vblank_time: Pointer to struct timeval which should receive the timestamp. - * @flags: Flags to pass to driver: - * 0 = Default. - * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler. - * @refcrtc: drm_crtc* of crtc which defines scanout timing. - * @mode: mode which defines the scanout timings - * - * Returns negative value on error, failure or if not supported in current + * Returns: + * Negative value on error, failure or if not supported in current * video mode: * - * -EINVAL - Invalid crtc. + * -EINVAL - Invalid CRTC. * -EAGAIN - Temporary unavailable, e.g., called before initial modeset. * -ENOTSUPP - Function not supported in current display mode. * -EIO - Failed, e.g., due to failed scanout position query. @@ -641,23 +673,23 @@ static struct timeval get_drm_timestamp(void) /** * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent - * vblank interval. - * + * vblank interval * @dev: DRM device - * @crtc: which crtc's vblank timestamp to retrieve + * @crtc: which CRTC's vblank timestamp to retrieve * @tvblank: Pointer to target struct timeval which should receive the timestamp * @flags: Flags to pass to driver: - * 0 = Default. - * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler. + * 0 = Default, + * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler * * Fetches the system timestamp corresponding to the time of the most recent - * vblank interval on specified crtc. May call into kms-driver to + * vblank interval on specified CRTC. May call into kms-driver to * compute the timestamp with a high-precision GPU specific method. * * Returns zero if timestamp originates from uncorrected do_gettimeofday() * call, i.e., it isn't very precisely locked to the true vblank. * - * Returns non-zero if timestamp is considered to be very precise. + * Returns: + * Non-zero if timestamp is considered to be very precise, zero otherwise. */ u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc, struct timeval *tvblank, unsigned flags) @@ -692,6 +724,9 @@ EXPORT_SYMBOL(drm_get_last_vbltimestamp); * Fetches the "cooked" vblank count value that represents the number of * vblank events since the system was booted, including lost events due to * modesetting activity. + * + * Returns: + * The software vblank counter. */ u32 drm_vblank_count(struct drm_device *dev, int crtc) { @@ -710,8 +745,7 @@ EXPORT_SYMBOL(drm_vblank_count); * Fetches the "cooked" vblank count value that represents the number of * vblank events since the system was booted, including lost events due to * modesetting activity. Returns corresponding system timestamp of the time - * of the vblank interval that corresponds to the current value vblank counter - * value. + * of the vblank interval that corresponds to the current vblank counter value. */ u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc, struct timeval *vblanktime) @@ -882,7 +916,7 @@ static int drm_vblank_enable(struct drm_device *dev, int crtc) * Acquire a reference count on vblank events to avoid having them disabled * while in use. * - * RETURNS + * Returns: * Zero on success, nonzero on failure. */ int drm_vblank_get(struct drm_device *dev, int crtc) @@ -930,6 +964,13 @@ EXPORT_SYMBOL(drm_vblank_put); * drm_vblank_off - disable vblank events on a CRTC * @dev: DRM device * @crtc: CRTC in question + * + * Drivers can use this function to shut down the vblank interrupt handling when + * disabling a crtc. This function ensures that the latest vblank frame count is + * stored so that drm_vblank_on() can restore it again. + * + * Drivers must use this function when the hardware vblank counter can get + * reset, e.g. when suspending. */ void drm_vblank_off(struct drm_device *dev, int crtc) { @@ -966,6 +1007,11 @@ EXPORT_SYMBOL(drm_vblank_off); * drm_vblank_on - enable vblank events on a CRTC * @dev: DRM device * @crtc: CRTC in question + * + * This functions restores the vblank interrupt state captured with + * drm_vblank_off() again. Note that calls to drm_vblank_on() and + * drm_vblank_off() can be unbalanced and so can also be unconditionaly called + * in driver load code to reflect the current hardware state of the crtc. */ void drm_vblank_on(struct drm_device *dev, int crtc) { @@ -986,6 +1032,21 @@ EXPORT_SYMBOL(drm_vblank_on); * * Account for vblank events across mode setting events, which will likely * reset the hardware frame counter. + * + * This is done by grabbing a temporary vblank reference to ensure that the + * vblank interrupt keeps running across the modeset sequence. With this the + * software-side vblank frame counting will ensure that there are no jumps or + * discontinuities. + * + * Unfortunately this approach is racy and also doesn't work when the vblank + * interrupt stops running, e.g. across system suspend resume. It is therefore + * highly recommended that drivers use the newer drm_vblank_off() and + * drm_vblank_on() instead. drm_vblank_pre_modeset() only works correctly when + * using "cooked" software vblank frame counters and not relying on any hardware + * counters. + * + * Drivers must call drm_vblank_post_modeset() when re-enabling the same crtc + * again. */ void drm_vblank_pre_modeset(struct drm_device *dev, int crtc) { @@ -1007,6 +1068,14 @@ void drm_vblank_pre_modeset(struct drm_device *dev, int crtc) } EXPORT_SYMBOL(drm_vblank_pre_modeset); +/** + * drm_vblank_post_modeset - undo drm_vblank_pre_modeset changes + * @dev: DRM device + * @crtc: CRTC in question + * + * This function again drops the temporary vblank reference acquired in + * drm_vblank_pre_modeset. + */ void drm_vblank_post_modeset(struct drm_device *dev, int crtc) { unsigned long irqflags; @@ -1028,7 +1097,7 @@ void drm_vblank_post_modeset(struct drm_device *dev, int crtc) } EXPORT_SYMBOL(drm_vblank_post_modeset); -/** +/* * drm_modeset_ctl - handle vblank event counter changes across mode switch * @DRM_IOCTL_ARGS: standard ioctl arguments * @@ -1141,7 +1210,7 @@ err_put: return ret; } -/** +/* * Wait for VBLANK. * * \param inode device inode. @@ -1152,7 +1221,7 @@ err_put: * * This function enables the vblank interrupt on the pipe requested, then * sleeps waiting for the requested sequence number to occur, and drops - * the vblank interrupt refcount afterwards. (vblank irq disable follows that + * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that * after a timeout with no further vblank waits scheduled). */ int drm_wait_vblank(struct drm_device *dev, void *data,