From: chunhui dai <chunhui....@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.hs...@mediatek.com>
Signed-off-by: chunhui dai <chunhui....@mediatek.com>
---
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
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