From mboxrd@z Thu Jan 1 00:00:00 1970 From: bibby.hsieh@mediatek.com (Bibby Hsieh) Date: Fri, 21 Sep 2018 11:28:11 +0800 Subject: [PATCH v3 01/12] drm/mediatek: add refcount for DPI power on/off In-Reply-To: <20180921032822.30771-1-bibby.hsieh@mediatek.com> References: <20180921032822.30771-1-bibby.hsieh@mediatek.com> Message-ID: <20180921032822.30771-2-bibby.hsieh@mediatek.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: chunhui dai After the kernel 4.4, the DRM disable flow was changed, if DPI was disableed before CRTC, it will cause warning message as following: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1339 at ../../linux/linux-4.4.24-mtk/drivers/gpu/drm/drm_irq.c:1326 drm_wait_one_vblank+0x188/0x18c() vblank wait timed out on crtc 0 Modules linked in: bridge mt8521p_ir_shim(O) i2c_eeprom(O) mtk_m4(O) fuse_ctrl(O) virtual_block(O) caamkeys(PO) chk(PO) amperctl(O) ledctl(O) apple_auth(PO) micctl(O) sensors(PO) lla(O) sdd(PO) ice40_fpga(O) psmon(O) event_queue(PO) utils(O) blackbox(O) CPU: 0 PID: 1339 Comm: kworker/0:1 Tainted: P W O 4.4.24 #1 Hardware name: Mediatek Cortex-A7 (Device Tree) Workqueue: events drm_mode_rmfb_work_fn [] (unwind_backtrace) from [] (show_stack+0x20/0x24) [] (show_stack) from [] (dump_stack+0x98/0xac) [] (dump_stack) from [] (warn_slowpath_common+0x94/0xc4) [] (warn_slowpath_common) from [] (warn_slowpath_fmt+0x40/0x48) [] (warn_slowpath_fmt) from [] (drm_wait_one_vblank+0x188/0x18c) [] (drm_wait_one_vblank) from [] (drm_crtc_wait_one_vblank+0x28/0x2c) [] (drm_crtc_wait_one_vblank) from [] (mtk_drm_crtc_disable+0x78/0x240) [] (mtk_drm_crtc_disable) from [] (drm_atomic_helper_commit_modeset_disables+0x128/0x3b8) [] (drm_atomic_helper_commit_modeset_disables) from [] (mtk_atomic_complete+0x74/0xb4) [] (mtk_atomic_complete) from [] (mtk_atomic_commit+0x68/0x98) [] (mtk_atomic_commit) from [] (drm_atomic_commit+0x54/0x74) [] (drm_atomic_commit) from [] (drm_atomic_helper_set_config+0x7c/0xa0) [] (drm_atomic_helper_set_config) from [] (drm_mode_set_config_internal+0x68/0xe4) [] (drm_mode_set_config_internal) from [] (drm_framebuffer_remove+0xe4/0x120) [] (drm_framebuffer_remove) from [] (drm_mode_rmfb_work_fn+0x48/0x58) [] (drm_mode_rmfb_work_fn) from [] (process_one_work+0x154/0x50c) [] (process_one_work) from [] (worker_thread+0x284/0x568) [] (worker_thread) from [] (kthread+0xec/0x104) [] (kthread) from [] (ret_from_fork+0x14/0x3c) ---[ end trace 12ae5358e992abd5 ]--- so, we add refcount for DPI power on/off to protect the flow. Signed-off-by: Bibby Hsieh Signed-off-by: chunhui dai --- drivers/gpu/drm/mediatek/mtk_dpi.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c index 6c0ea39d5739..d9373e67d328 100644 --- a/drivers/gpu/drm/mediatek/mtk_dpi.c +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c @@ -77,6 +77,7 @@ struct mtk_dpi { enum mtk_dpi_out_bit_num bit_num; enum mtk_dpi_out_channel_swap channel_swap; bool power_sta; + int refcount; u8 power_ctl; }; @@ -369,6 +370,12 @@ static void mtk_dpi_config_color_format(struct mtk_dpi *dpi, static void mtk_dpi_power_off(struct mtk_dpi *dpi, enum mtk_dpi_power_ctl pctl) { + if (WARN_ON(dpi->refcount == 0)) + return; + + if (--dpi->refcount != 0) + return; + dpi->power_ctl &= ~pctl; if ((dpi->power_ctl & DPI_POWER_START) || @@ -388,14 +395,17 @@ static int mtk_dpi_power_on(struct mtk_dpi *dpi, enum mtk_dpi_power_ctl pctl) { int ret; + if (++dpi->refcount != 1) + return 0; + dpi->power_ctl |= pctl; if (!(dpi->power_ctl & DPI_POWER_START) && !(dpi->power_ctl & DPI_POWER_ENABLE)) - return 0; + goto err_refcount; if (dpi->power_sta) - return 0; + goto err_refcount; ret = clk_prepare_enable(dpi->engine_clk); if (ret) { @@ -417,6 +427,8 @@ static int mtk_dpi_power_on(struct mtk_dpi *dpi, enum mtk_dpi_power_ctl pctl) clk_disable_unprepare(dpi->engine_clk); err_eng: dpi->power_ctl &= ~pctl; +err_refcount: + dpi->refcount--; return ret; } -- 2.12.5.2.gbdf23ab