From: Daniel Vetter <daniel.vetter@xxxxxxxx> Only when vblanks are supported ofc. Some drivers do this already, but most unfortunately missed it. This opens up bugs after driver load, before the crtc is enabled for the first time. syzbot spotted this when loading vkms as a secondary output. Given how many drivers are buggy it's best to solve this once and for all in shared helper code. Aside from moving the few existing calls to drm_crtc_vblank_reset into helpers (i915 doesn't use helpers, so keeps its own) I think the regression risk is minimal: atomic helpers already rely on drivers calling drm_crtc_vblank_on/off correctly in their hooks when they support vblanks. And driver that's failing to handle vblanks after this is missing those calls already, and vblanks could only work by accident when enabling a CRTC for the first time right after boot. Big thanks to Tetsuo for helping track down what's going wrong here. There's only a few drivers which already had the necessary call and needed some updating: - komeda, atmel and tidss also needed to be changed to call __drm_atomic_helper_crtc_reset() intead of open coding it - tegra and msm even had it in the same place already, just code motion, and malidp already uses __drm_atomic_helper_crtc_reset(). - Laurent noticed that rcar-du and omap open-code their crtc reset and hence would actually be broken by this patch now. So fix them up by reusing the helpers, which brings the drm_crtc_vblank_reset() back. Only call left is in i915, which doesn't use drm_mode_config_reset, but has its own fastboot infrastructure. So that's the only case where we actually want this in the driver still. I've also reviewed all other drivers which set up vblank support with drm_vblank_init. After the previous patch fixing mxsfb all atomic drivers do call drm_crtc_vblank_on/off as they should, the remaining drivers are either legacy kms or legacy dri1 drivers, so not affected by this change to atomic helpers. v2: Use the drm_dev_has_vblank() helper. v3: Laurent pointed out that omap and rcar-du used drm_crtc_vblank_off instead of drm_crtc_vblank_reset. Adjust them too. v4: Laurent noticed that rcar-du and omap open-code their crtc reset and hence would actually be broken by this patch now. So fix them up by reusing the helpers, which brings the drm_crtc_vblank_reset() back. v5: also mention rcar-du and ompadrm in the proper commit message above (Laurent). Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> Acked-by: Maxime Ripard <mripard@xxxxxxxxxx> Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> Acked-by: Liviu Dudau <liviu.dudau@xxxxxxx> Acked-by: Thierry Reding <treding@xxxxxxxxxx> Link: https://syzkaller.appspot.com/bug?id=0ba17d70d062b2595e1f061231474800f076c7cb Reported-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Reported-by: syzbot+0871b14ca2e2fb64f6e3@xxxxxxxxxxxxxxxxxxxxxxxxx Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Cc: "James (Qian) Wang" <james.qian.wang@xxxxxxx> Cc: Liviu Dudau <liviu.dudau@xxxxxxx> Cc: Mihail Atanassov <mihail.atanassov@xxxxxxx> Cc: Brian Starkey <brian.starkey@xxxxxxx> Cc: Sam Ravnborg <sam@xxxxxxxxxxxx> Cc: Boris Brezillon <bbrezillon@xxxxxxxxxx> Cc: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx> Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> Cc: Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx> Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> Cc: Maxime Ripard <mripard@xxxxxxxxxx> Cc: Thomas Zimmermann <tzimmermann@xxxxxxx> Cc: David Airlie <airlied@xxxxxxxx> Cc: Daniel Vetter <daniel@xxxxxxxx> Cc: Thierry Reding <thierry.reding@xxxxxxxxx> Cc: Jonathan Hunter <jonathanh@xxxxxxxxxx> Cc: Jyri Sarha <jsarha@xxxxxx> Cc: Tomi Valkeinen <tomi.valkeinen@xxxxxx> Cc: Rob Clark <robdclark@xxxxxxxxx> Cc: Sean Paul <seanpaul@xxxxxxxxxxxx> Cc: Brian Masney <masneyb@xxxxxxxxxxxxx> Cc: Emil Velikov <emil.velikov@xxxxxxxxxxxxx> Cc: zhengbin <zhengbin13@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: linux-tegra@xxxxxxxxxxxxxxx Cc: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Cc: linux-renesas-soc@xxxxxxxxxxxxxxx Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20200612160056.2082681-1-daniel.vetter@xxxxxxxx (cherry picked from commit 51f644b40b4b794b28b982fdd5d0dd8ee63f9272) Signed-off-by: George Kennedy <george.kennedy@xxxxxxxxxx> Conflicts: drivers/gpu/drm/tidss/tidss_crtc.c drivers/gpu/drm/tidss/tidss_kms.c --- drivers/gpu/drm/arm/display/komeda/komeda_crtc.c | 7 ++----- drivers/gpu/drm/arm/malidp_drv.c | 1 - drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c | 7 ++----- drivers/gpu/drm/drm_atomic_state_helper.c | 4 ++++ drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c | 2 -- drivers/gpu/drm/omapdrm/omap_crtc.c | 8 +++++--- drivers/gpu/drm/omapdrm/omap_drv.c | 4 ---- drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 6 +----- drivers/gpu/drm/tegra/dc.c | 1 - 9 files changed, 14 insertions(+), 26 deletions(-) diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c index 52c4256..d301e55 100644 --- a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c +++ b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c @@ -440,10 +440,8 @@ static void komeda_crtc_reset(struct drm_crtc *crtc) crtc->state = NULL; state = kzalloc(sizeof(*state), GFP_KERNEL); - if (state) { - crtc->state = &state->base; - crtc->state->crtc = crtc; - } + if (state) + __drm_atomic_helper_crtc_reset(crtc, &state->base); } static struct drm_crtc_state * @@ -564,7 +562,6 @@ static int komeda_crtc_add(struct komeda_kms_dev *kms, return err; drm_crtc_helper_add(crtc, &komeda_crtc_helper_funcs); - drm_crtc_vblank_reset(crtc); crtc->port = kcrtc->master->of_output_port; diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c index 333b88a..566b183 100644 --- a/drivers/gpu/drm/arm/malidp_drv.c +++ b/drivers/gpu/drm/arm/malidp_drv.c @@ -865,7 +865,6 @@ static int malidp_bind(struct device *dev) drm->irq_enabled = true; ret = drm_vblank_init(drm, drm->mode_config.num_crtc); - drm_crtc_vblank_reset(&malidp->crtc); if (ret < 0) { DRM_ERROR("failed to initialise vblank\n"); goto vblank_fail; diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c index 1098513..ce246b9 100644 --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c @@ -411,10 +411,8 @@ static void atmel_hlcdc_crtc_reset(struct drm_crtc *crtc) } state = kzalloc(sizeof(*state), GFP_KERNEL); - if (state) { - crtc->state = &state->base; - crtc->state->crtc = crtc; - } + if (state) + __drm_atomic_helper_crtc_reset(crtc, &state->base); } static struct drm_crtc_state * @@ -528,7 +526,6 @@ int atmel_hlcdc_crtc_create(struct drm_device *dev) } drm_crtc_helper_add(&crtc->base, &lcdc_crtc_helper_funcs); - drm_crtc_vblank_reset(&crtc->base); drm_mode_crtc_set_gamma_size(&crtc->base, ATMEL_HLCDC_CLUT_SIZE); drm_crtc_enable_color_mgmt(&crtc->base, 0, false, diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c index d0a937f..9c16936 100644 --- a/drivers/gpu/drm/drm_atomic_state_helper.c +++ b/drivers/gpu/drm/drm_atomic_state_helper.c @@ -31,6 +31,7 @@ #include <drm/drm_device.h> #include <drm/drm_plane.h> #include <drm/drm_print.h> +#include <drm/drm_vblank.h> #include <drm/drm_writeback.h> #include <linux/slab.h> @@ -76,6 +77,9 @@ if (crtc_state) crtc_state->crtc = crtc; + if (drm_dev_has_vblank(crtc->dev)) + drm_crtc_vblank_reset(crtc); + crtc->state = crtc_state; } EXPORT_SYMBOL(__drm_atomic_helper_crtc_reset); diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c index 3951468..dbfd113 100644 --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c @@ -1043,8 +1043,6 @@ static void mdp5_crtc_reset(struct drm_crtc *crtc) mdp5_crtc_destroy_state(crtc, crtc->state); __drm_atomic_helper_crtc_reset(crtc, &mdp5_cstate->base); - - drm_crtc_vblank_reset(crtc); } static const struct drm_crtc_funcs mdp5_crtc_funcs = { diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c b/drivers/gpu/drm/omapdrm/omap_crtc.c index f5e1880..cfeb424 100644 --- a/drivers/gpu/drm/omapdrm/omap_crtc.c +++ b/drivers/gpu/drm/omapdrm/omap_crtc.c @@ -698,14 +698,16 @@ static int omap_crtc_atomic_get_property(struct drm_crtc *crtc, static void omap_crtc_reset(struct drm_crtc *crtc) { + struct omap_crtc_state *state; + if (crtc->state) __drm_atomic_helper_crtc_destroy_state(crtc->state); kfree(crtc->state); - crtc->state = kzalloc(sizeof(struct omap_crtc_state), GFP_KERNEL); - if (crtc->state) - crtc->state->crtc = crtc; + state = kzalloc(sizeof(*state), GFP_KERNEL); + if (state) + __drm_atomic_helper_crtc_reset(crtc, &state->base); } static struct drm_crtc_state * diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c index 2983c00..672b0d3 100644 --- a/drivers/gpu/drm/omapdrm/omap_drv.c +++ b/drivers/gpu/drm/omapdrm/omap_drv.c @@ -557,7 +557,6 @@ static int omapdrm_init(struct omap_drm_private *priv, struct device *dev) { const struct soc_device_attribute *soc; struct drm_device *ddev; - unsigned int i; int ret; DBG("%s", dev_name(dev)); @@ -604,9 +603,6 @@ static int omapdrm_init(struct omap_drm_private *priv, struct device *dev) goto err_cleanup_modeset; } - for (i = 0; i < priv->num_pipes; i++) - drm_crtc_vblank_off(priv->pipes[i].crtc); - omap_fbdev_init(ddev); drm_kms_helper_poll_init(ddev); diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c index 2da46e3..6d0280c 100644 --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c @@ -910,8 +910,7 @@ static void rcar_du_crtc_reset(struct drm_crtc *crtc) state->crc.source = VSP1_DU_CRC_NONE; state->crc.index = 0; - crtc->state = &state->state; - crtc->state->crtc = crtc; + __drm_atomic_helper_crtc_reset(crtc, &state->state); } static int rcar_du_crtc_enable_vblank(struct drm_crtc *crtc) @@ -1196,9 +1195,6 @@ int rcar_du_crtc_create(struct rcar_du_group *rgrp, unsigned int swindex, drm_crtc_helper_add(crtc, &crtc_helper_funcs); - /* Start with vertical blanking interrupt reporting disabled. */ - drm_crtc_vblank_off(crtc); - /* Register the interrupt handler. */ if (rcar_du_has(rcdu, RCAR_DU_FEATURE_CRTC_IRQ_CLOCK)) { /* The IRQ's are associated with the CRTC (sw)index. */ diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c index 617cbe4..75c7068 100644 --- a/drivers/gpu/drm/tegra/dc.c +++ b/drivers/gpu/drm/tegra/dc.c @@ -1166,7 +1166,6 @@ static void tegra_crtc_reset(struct drm_crtc *crtc) tegra_crtc_atomic_destroy_state(crtc, crtc->state); __drm_atomic_helper_crtc_reset(crtc, &state->base); - drm_crtc_vblank_reset(crtc); } static struct drm_crtc_state * -- 1.8.3.1
