From: chunhui dai chunhui.dai@mediatek.com
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 [<c001a710>] (unwind_backtrace) from [<c00151e4>] (show_stack+0x20/0x24) [<c00151e4>] (show_stack) from [<c027961c>] (dump_stack+0x98/0xac) [<c027961c>] (dump_stack) from [<c002ac54>] (warn_slowpath_common+0x94/0xc4) [<c002ac54>] (warn_slowpath_common) from [<c002acc4>] (warn_slowpath_fmt+0x40/0x48) [<c002acc4>] (warn_slowpath_fmt) from [<c03307ac>] (drm_wait_one_vblank+0x188/0x18c) [<c03307ac>] (drm_wait_one_vblank) from [<c03307d8>] (drm_crtc_wait_one_vblank+0x28/0x2c) [<c03307d8>] (drm_crtc_wait_one_vblank) from [<c034f48c>] (mtk_drm_crtc_disable+0x78/0x240) [<c034f48c>] (mtk_drm_crtc_disable) from [<c03240d4>] (drm_atomic_helper_commit_modeset_disables+0x128/0x3b8) [<c03240d4>] (drm_atomic_helper_commit_modeset_disables) from [<c0350a7c>] (mtk_atomic_complete+0x74/0xb4) [<c0350a7c>] (mtk_atomic_complete) from [<c0350b24>] (mtk_atomic_commit+0x68/0x98) [<c0350b24>] (mtk_atomic_commit) from [<c034ab48>] (drm_atomic_commit+0x54/0x74) [<c034ab48>] (drm_atomic_commit) from [<c0325c4c>] (drm_atomic_helper_set_config+0x7c/0xa0) [<c0325c4c>] (drm_atomic_helper_set_config) from [<c0338594>] (drm_mode_set_config_internal+0x68/0xe4) [<c0338594>] (drm_mode_set_config_internal) from [<c033967c>] (drm_framebuffer_remove+0xe4/0x120) [<c033967c>] (drm_framebuffer_remove) from [<c0339700>] (drm_mode_rmfb_work_fn+0x48/0x58) [<c0339700>] (drm_mode_rmfb_work_fn) from [<c0043a38>] (process_one_work+0x154/0x50c) [<c0043a38>] (process_one_work) from [<c0044074>] (worker_thread+0x284/0x568) [<c0044074>] (worker_thread) from [<c0049dc4>] (kthread+0xec/0x104) [<c0049dc4>] (kthread) from [<c0010678>] (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 bibby.hsieh@mediatek.com Signed-off-by: chunhui dai chunhui.dai@mediatek.com Reviewed-by: CK Hu ck.hu@mediatek.com --- drivers/gpu/drm/mediatek/mtk_dpi.c | 43 ++++++++++++-------------------------- 1 file changed, 13 insertions(+), 30 deletions(-)
diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c index 6c0ea39d5739..5ede1ddbaa1a 100644 --- a/drivers/gpu/drm/mediatek/mtk_dpi.c +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c @@ -76,8 +76,7 @@ struct mtk_dpi { enum mtk_dpi_out_yc_map yc_map; enum mtk_dpi_out_bit_num bit_num; enum mtk_dpi_out_channel_swap channel_swap; - bool power_sta; - u8 power_ctl; + int refcount; };
static inline struct mtk_dpi *mtk_dpi_from_encoder(struct drm_encoder *e) @@ -90,11 +89,6 @@ enum mtk_dpi_polarity { MTK_DPI_POLARITY_FALLING, };
-enum mtk_dpi_power_ctl { - DPI_POWER_START = BIT(0), - DPI_POWER_ENABLE = BIT(1), -}; - struct mtk_dpi_polarities { enum mtk_dpi_polarity de_pol; enum mtk_dpi_polarity ck_pol; @@ -367,40 +361,30 @@ 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) +static void mtk_dpi_power_off(struct mtk_dpi *dpi) { - dpi->power_ctl &= ~pctl; - - if ((dpi->power_ctl & DPI_POWER_START) || - (dpi->power_ctl & DPI_POWER_ENABLE)) + if (WARN_ON(dpi->refcount == 0)) return;
- if (!dpi->power_sta) + if (--dpi->refcount != 0) return;
mtk_dpi_disable(dpi); clk_disable_unprepare(dpi->pixel_clk); clk_disable_unprepare(dpi->engine_clk); - dpi->power_sta = false; }
-static int mtk_dpi_power_on(struct mtk_dpi *dpi, enum mtk_dpi_power_ctl pctl) +static int mtk_dpi_power_on(struct mtk_dpi *dpi) { int ret;
- dpi->power_ctl |= pctl; - - if (!(dpi->power_ctl & DPI_POWER_START) && - !(dpi->power_ctl & DPI_POWER_ENABLE)) - return 0; - - if (dpi->power_sta) + if (++dpi->refcount != 1) return 0;
ret = clk_prepare_enable(dpi->engine_clk); if (ret) { dev_err(dpi->dev, "Failed to enable engine clock: %d\n", ret); - goto err_eng; + goto err_refcount; }
ret = clk_prepare_enable(dpi->pixel_clk); @@ -410,13 +394,12 @@ static int mtk_dpi_power_on(struct mtk_dpi *dpi, enum mtk_dpi_power_ctl pctl) }
mtk_dpi_enable(dpi); - dpi->power_sta = true; return 0;
err_pixel: clk_disable_unprepare(dpi->engine_clk); -err_eng: - dpi->power_ctl &= ~pctl; +err_refcount: + dpi->refcount--; return ret; }
@@ -552,14 +535,14 @@ static void mtk_dpi_encoder_disable(struct drm_encoder *encoder) { struct mtk_dpi *dpi = mtk_dpi_from_encoder(encoder);
- mtk_dpi_power_off(dpi, DPI_POWER_ENABLE); + mtk_dpi_power_off(dpi); }
static void mtk_dpi_encoder_enable(struct drm_encoder *encoder) { struct mtk_dpi *dpi = mtk_dpi_from_encoder(encoder);
- mtk_dpi_power_on(dpi, DPI_POWER_ENABLE); + mtk_dpi_power_on(dpi); mtk_dpi_set_display_mode(dpi, &dpi->mode); }
@@ -582,14 +565,14 @@ static void mtk_dpi_start(struct mtk_ddp_comp *comp) { struct mtk_dpi *dpi = container_of(comp, struct mtk_dpi, ddp_comp);
- mtk_dpi_power_on(dpi, DPI_POWER_START); + mtk_dpi_power_on(dpi); }
static void mtk_dpi_stop(struct mtk_ddp_comp *comp) { struct mtk_dpi *dpi = container_of(comp, struct mtk_dpi, ddp_comp);
- mtk_dpi_power_off(dpi, DPI_POWER_START); + mtk_dpi_power_off(dpi); }
static const struct mtk_ddp_comp_funcs mtk_dpi_funcs = {