RE: [PATCH v6 1/1] drm/bridge: it6505: fix hibernate to resume no display issue

From: kuro.chung
Date: Mon May 06 2024 - 05:16:53 EST

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-----Original Message-----
From: Robert Foss <rfoss@xxxxxxxxxx>
Sent: Tuesday, April 23, 2024 9:50 PM
To: Kuro Chung (鐘仕廷) <kuro.chung@xxxxxxxxxx>
Cc: Allen Chen <allen.chen@xxxxxxxxxx>; Pin-yen Lin <treapking@xxxxxxxxxxxx>; Kenneth Hung (洪家倫) <Kenneth.Hung@xxxxxxxxxx>; Kuro Chung <kuro.chung@xxxxxxxxxxxxxxxxxxxxxxxxxxx>; Andrzej Hajda <andrzej.hajda@xxxxxxxxx>; Neil Armstrong <neil.armstrong@xxxxxxxxxx>; Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>; Jonas Karlman <jonas@xxxxxxxxx>; Jernej Skrabec <jernej.skrabec@xxxxxxxxx>; Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>; Maxime Ripard <mripard@xxxxxxxxxx>; Thomas Zimmermann <tzimmermann@xxxxxxx>; David Airlie <airlied@xxxxxxxxx>; Daniel Vetter <daniel@xxxxxxxx>; open list:DRM DRIVERS <dri-devel@xxxxxxxxxxxxxxxxxxxxx>; open list <linux-kernel@xxxxxxxxxxxxxxx>
Subject: Re: [PATCH v6 1/1] drm/bridge: it6505: fix hibernate to resume no display issue

On Tue, Apr 23, 2024 at 10:16 AM kuro <kuro.chung@xxxxxxxxxx> wrote:
>
> From: Kuro <kuro.chung@xxxxxxxxxx>
>
> ITE added a FIFO reset bit for input video. When system power resume,
> the TTL input of it6505 may get some noise before video signal stable
> and the hardware function reset is required.
> But the input FIFO reset will also trigger error interrupts of output module rising.
> Thus, it6505 have to wait a period can clear those expected error
> interrupts caused by manual hardware reset in one interrupt handler calling to avoid interrupt looping.
>
> Signed-off-by: Kuro Chung <kuro.chung@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
>
> ---
> drivers/gpu/drm/bridge/ite-it6505.c | 73
> +++++++++++++++++++----------
> 1 file changed, 49 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/ite-it6505.c
> b/drivers/gpu/drm/bridge/ite-it6505.c
> index b53da9bb65a16..ae7f4c7ec6dd0 100644
> --- a/drivers/gpu/drm/bridge/ite-it6505.c
> +++ b/drivers/gpu/drm/bridge/ite-it6505.c
> @@ -1317,9 +1317,15 @@ static void it6505_video_reset(struct it6505 *it6505)
> it6505_link_reset_step_train(it6505);
> it6505_set_bits(it6505, REG_DATA_MUTE_CTRL, EN_VID_MUTE, EN_VID_MUTE);
> it6505_set_bits(it6505, REG_INFOFRAME_CTRL, EN_VID_CTRL_PKT, 0x00);
> - it6505_set_bits(it6505, REG_RESET_CTRL, VIDEO_RESET, VIDEO_RESET);
> +
> + it6505_set_bits(it6505, REG_VID_BUS_CTRL1, TX_FIFO_RESET, 0x02);
> + it6505_set_bits(it6505, REG_VID_BUS_CTRL1, TX_FIFO_RESET,
> + 0x00);
> +
> it6505_set_bits(it6505, REG_501_FIFO_CTRL, RST_501_FIFO, RST_501_FIFO);
> it6505_set_bits(it6505, REG_501_FIFO_CTRL, RST_501_FIFO,
> 0x00);
> +
> + it6505_set_bits(it6505, REG_RESET_CTRL, VIDEO_RESET, VIDEO_RESET);
> + usleep_range(1000, 2000);
> it6505_set_bits(it6505, REG_RESET_CTRL, VIDEO_RESET, 0x00);

Can any of these magic values be defined as macros?
-> I will modify the code 0x02 to TX_FIFO_RESET

> }
>
> @@ -2249,12 +2255,11 @@ static void it6505_link_training_work(struct work_struct *work)
> if (ret) {
> it6505->auto_train_retry = AUTO_TRAIN_RETRY;
> it6505_link_train_ok(it6505);
> - return;
> } else {
> it6505->auto_train_retry--;
> + it6505_dump(it6505);
> }
>
> - it6505_dump(it6505);
> }
>
> static void it6505_plugged_status_to_codec(struct it6505 *it6505) @@
> -2475,31 +2480,53 @@ static void it6505_irq_link_train_fail(struct it6505 *it6505)
> schedule_work(&it6505->link_works);
> }
>
> -static void it6505_irq_video_fifo_error(struct it6505 *it6505)
> +static bool it6505_test_bit(unsigned int bit, const unsigned int
> +*addr)
> {
> - struct device *dev = &it6505->client->dev;
> -
> - DRM_DEV_DEBUG_DRIVER(dev, "video fifo overflow interrupt");
> - it6505->auto_train_retry = AUTO_TRAIN_RETRY;
> - flush_work(&it6505->link_works);
> - it6505_stop_hdcp(it6505);
> - it6505_video_reset(it6505);
> + return 1 & (addr[bit / BITS_PER_BYTE] >> (bit %
> + BITS_PER_BYTE));
> }
>
> -static void it6505_irq_io_latch_fifo_overflow(struct it6505 *it6505)
> +static void it6505_irq_video_handler(struct it6505 *it6505, const int
> +*int_status)
> {
> struct device *dev = &it6505->client->dev;
> + int reg_0d, reg_int03;
>
> - DRM_DEV_DEBUG_DRIVER(dev, "IO latch fifo overflow interrupt");
> - it6505->auto_train_retry = AUTO_TRAIN_RETRY;
> - flush_work(&it6505->link_works);
> - it6505_stop_hdcp(it6505);
> - it6505_video_reset(it6505);
> -}
> + /*
> + * When video SCDT change with video not stable,
> + * Or video FIFO error, need video reset
> + */
>
> -static bool it6505_test_bit(unsigned int bit, const unsigned int
> *addr) -{
> - return 1 & (addr[bit / BITS_PER_BYTE] >> (bit % BITS_PER_BYTE));
> + if ((!it6505_get_video_status(it6505) &&
> + (it6505_test_bit(INT_SCDT_CHANGE, (unsigned int *) int_status))) ||
> + (it6505_test_bit(BIT_INT_IO_FIFO_OVERFLOW, (unsigned int *) int_status)) ||
> + (it6505_test_bit(BIT_INT_VID_FIFO_ERROR, (unsigned int
> + *) int_status))) {
> +
> + it6505->auto_train_retry = AUTO_TRAIN_RETRY;
> + flush_work(&it6505->link_works);
> + it6505_stop_hdcp(it6505);
> + it6505_video_reset(it6505);
> +
> + usleep_range(10000, 11000);
> +
> + /*
> + * Clear FIFO error IRQ to prevent fifo error -> reset loop
> + * HW will trigger SCDT change IRQ again when video stable
> + */
> +
> + reg_int03 = it6505_read(it6505, INT_STATUS_03);
> + reg_0d = it6505_read(it6505, REG_SYSTEM_STS);
> +
> + reg_int03 &= (BIT(INT_VID_FIFO_ERROR) | BIT(INT_IO_LATCH_FIFO_OVERFLOW));
> + it6505_write(it6505, INT_STATUS_03, reg_int03);
> +
> + DRM_DEV_DEBUG_DRIVER(dev, "reg08 = 0x%02x",
> + reg_int03);

Is this correct? Doesreg_int03 contain reg08?
-> #define INT_STATUS_03 0x08
-> yes, INT03 is reg08 (offset), reg08 is more readable.

> + DRM_DEV_DEBUG_DRIVER(dev, "reg0D = 0x%02x", reg_0d);
> +
> + return;
> + }
> +
> +
> + if (it6505_test_bit(INT_SCDT_CHANGE, (unsigned int *) int_status))
> + it6505_irq_scdt(it6505);
> }
>
> static irqreturn_t it6505_int_threaded_handler(int unused, void
> *data) @@ -2512,15 +2539,12 @@ static irqreturn_t it6505_int_threaded_handler(int unused, void *data)
> } irq_vec[] = {
> { BIT_INT_HPD, it6505_irq_hpd },
> { BIT_INT_HPD_IRQ, it6505_irq_hpd_irq },
> - { BIT_INT_SCDT, it6505_irq_scdt },
> { BIT_INT_HDCP_FAIL, it6505_irq_hdcp_fail },
> { BIT_INT_HDCP_DONE, it6505_irq_hdcp_done },
> { BIT_INT_AUX_CMD_FAIL, it6505_irq_aux_cmd_fail },
> { BIT_INT_HDCP_KSV_CHECK, it6505_irq_hdcp_ksv_check },
> { BIT_INT_AUDIO_FIFO_ERROR, it6505_irq_audio_fifo_error },
> { BIT_INT_LINK_TRAIN_FAIL, it6505_irq_link_train_fail },
> - { BIT_INT_VID_FIFO_ERROR, it6505_irq_video_fifo_error },
> - { BIT_INT_IO_FIFO_OVERFLOW, it6505_irq_io_latch_fifo_overflow },
> };
> int int_status[3], i;
>
> @@ -2550,6 +2574,7 @@ static irqreturn_t it6505_int_threaded_handler(int unused, void *data)
> if (it6505_test_bit(irq_vec[i].bit, (unsigned int *)int_status))
> irq_vec[i].handler(it6505);
> }
> + it6505_irq_video_handler(it6505, (unsigned int *)
> + int_status);
> }
>
> pm_runtime_put_sync(dev);
> --
> 2.25.1
>

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