diff mbox

[RFC,v3] drm: kirin: Add mode_valid logic to avoid mode clocks we can't generate

Message ID 1500400781-18162-1-git-send-email-john.stultz@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

John Stultz July 18, 2017, 5:59 p.m. UTC
Currently the hikey dsi logic cannot generate accurate byte
clocks values for all pixel clock values. Thus if a mode clock
is selected that cannot match the calculated byte clock, the
device will boot with a blank screen.

This patch uses the new mode_valid callback (many thanks to
Jose Abreu for upstreaming it!) to ensure we don't select
modes we cannot generate.

Also, since the ade crtc code will adjust the mode in mode_set,
this patch also adds a mode_fixup callback which we use to make
sure we are validating the mode clock that will eventually be
used.

Many thanks to Jose and Daniel for recent feedback. I think this
version is looking much nicer. But I'd still welcome any feedback
or suggestions!

Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Xinliang Liu <xinliang.liu@linaro.org>
Cc: Xinliang Liu <z.liuxinliang@hisilicon.com>
Cc: Rongrong Zou <zourongrong@gmail.com>
Cc: Xinwei Kong <kong.kongxinwei@hisilicon.com>
Cc: Chen Feng <puck.chen@hisilicon.com>
Cc: Jose Abreu <Jose.Abreu@synopsys.com>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
v2: Reworked to calculate if modeclock matches the phy's
    byteclock, rather then using a whitelist of known modes.

v3: Reworked to check across all possible crtcs (even though for
    us there is only one), and use mode_fixup instead of a custom
    function, as suggested by Jose and Daniel.
---
 drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c    | 62 +++++++++++++++++++++++++
 drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c | 14 ++++++
 2 files changed, 76 insertions(+)

Comments

Jose Abreu July 19, 2017, 10:16 a.m. UTC | #1
Hi John,


On 18-07-2017 18:59, John Stultz wrote:
> Currently the hikey dsi logic cannot generate accurate byte
> clocks values for all pixel clock values. Thus if a mode clock
> is selected that cannot match the calculated byte clock, the
> device will boot with a blank screen.
>
> This patch uses the new mode_valid callback (many thanks to
> Jose Abreu for upstreaming it!) to ensure we don't select
> modes we cannot generate.
>
> Also, since the ade crtc code will adjust the mode in mode_set,
> this patch also adds a mode_fixup callback which we use to make
> sure we are validating the mode clock that will eventually be
> used.
>
> Many thanks to Jose and Daniel for recent feedback. I think this
> version is looking much nicer. But I'd still welcome any feedback
> or suggestions!
>
> Cc: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Sean Paul <seanpaul@chromium.org>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Rob Clark <robdclark@gmail.com>
> Cc: Xinliang Liu <xinliang.liu@linaro.org>
> Cc: Xinliang Liu <z.liuxinliang@hisilicon.com>
> Cc: Rongrong Zou <zourongrong@gmail.com>
> Cc: Xinwei Kong <kong.kongxinwei@hisilicon.com>
> Cc: Chen Feng <puck.chen@hisilicon.com>
> Cc: Jose Abreu <Jose.Abreu@synopsys.com>
> Cc: Archit Taneja <architt@codeaurora.org>
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> ---
> v2: Reworked to calculate if modeclock matches the phy's
>     byteclock, rather then using a whitelist of known modes.
>
> v3: Reworked to check across all possible crtcs (even though for
>     us there is only one), and use mode_fixup instead of a custom
>     function, as suggested by Jose and Daniel.
> ---
>  drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c    | 62 +++++++++++++++++++++++++
>  drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c | 14 ++++++
>  2 files changed, 76 insertions(+)
>
> diff --git a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
> index f77dcfa..d7b5820 100644
> --- a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
> +++ b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
> @@ -603,6 +603,67 @@ static void dsi_encoder_enable(struct drm_encoder *encoder)
>  	dsi->enable = true;
>  }
>  
> +static enum drm_mode_status dsi_encoder_phy_mode_valid(struct drm_encoder *encoder,
> +					const struct drm_display_mode *mode)
> +{
> +	struct dw_dsi *dsi = encoder_to_dsi(encoder);
> +	struct mipi_phy_params phy;
> +	u32 bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
> +	u32 req_kHz, act_kHz, lane_byte_clk_kHz;
> +
> +	/* Calculate the lane byte clk using the adjusted mode clk */
> +	memset(&phy, 0, sizeof(phy));
> +	req_kHz = mode->clock * bpp / dsi->lanes;
> +	act_kHz = dsi_calc_phy_rate(req_kHz, &phy);
> +	lane_byte_clk_kHz = act_kHz / 8;
> +
> +	DRM_DEBUG_DRIVER("Checking mode %ix%i-%i@%i clock: %i...",
> +			mode->hdisplay, mode->vdisplay, bpp,
> +			drm_mode_vrefresh(mode), mode->clock);
> +
> +	/*
> +	 * Make sure the adjused mode clock and the lane byte clk
> +	 * have a common denominator base frequency
> +	 */
> +	if (mode->clock/dsi->lanes == lane_byte_clk_kHz/3) {
> +		DRM_DEBUG_DRIVER("OK!\n");
> +		return MODE_OK;
> +	}
> +
> +	DRM_DEBUG_DRIVER("BAD!\n");
> +	return MODE_BAD;
> +}
> +
> +static enum drm_mode_status dsi_encoder_mode_valid(struct drm_encoder *encoder,
> +					const struct drm_display_mode *mode)
> +
> +{
> +	const struct drm_crtc_helper_funcs *crtc_funcs = NULL;
> +	struct drm_crtc *crtc = NULL;
> +	struct drm_display_mode adj_mode;
> +	int ret;

This int should be an enum drm_mode_status ...

> +
> +	memcpy(&adj_mode, mode, sizeof(adj_mode));

Maybe you should move this to the loop so that you pass a "clean"
adjusted mode (i.e. adj_mode == mode) for each crtc. You could
also use drm_mode_duplicate()/drm_mode_destroy() ...

> +
> +	/*
> +	 * The crtc might adjust the mode, so go through the
> +	 * possible crtcs (technically just one) and call
> +	 * mode_fixup to figure out the adjusted mode before we
> +	 * validate it.
> +	 */
> +	drm_for_each_crtc(crtc, encoder->dev) {
> +		crtc_funcs = crtc->helper_private;
> +		if (crtc_funcs && crtc_funcs->mode_fixup)
> +			ret = crtc_funcs->mode_fixup(crtc, mode,
> +							&adj_mode);

No return check?

Best regards,
Jose Miguel Abreu

> +
> +		ret = dsi_encoder_phy_mode_valid(encoder, &adj_mode);
> +		if (ret != MODE_OK)
> +			return ret;
> +	}
> +	return MODE_OK;
> +}
> +
>  static void dsi_encoder_mode_set(struct drm_encoder *encoder,
>  				 struct drm_display_mode *mode,
>  				 struct drm_display_mode *adj_mode)
> @@ -622,6 +683,7 @@ static int dsi_encoder_atomic_check(struct drm_encoder *encoder,
>  
>  static const struct drm_encoder_helper_funcs dw_encoder_helper_funcs = {
>  	.atomic_check	= dsi_encoder_atomic_check,
> +	.mode_valid	= dsi_encoder_mode_valid,
>  	.mode_set	= dsi_encoder_mode_set,
>  	.enable		= dsi_encoder_enable,
>  	.disable	= dsi_encoder_disable
> diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c
> index c96c228..dec7f4e 100644
> --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c
> +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c
> @@ -178,6 +178,19 @@ static void ade_init(struct ade_hw_ctx *ctx)
>  			FRM_END_START_MASK, REG_EFFECTIVE_IN_ADEEN_FRMEND);
>  }
>  
> +static bool ade_crtc_mode_fixup(struct drm_crtc *crtc,
> +				const struct drm_display_mode *mode,
> +				struct drm_display_mode *adjusted_mode)
> +{
> +	struct ade_crtc *acrtc = to_ade_crtc(crtc);
> +	struct ade_hw_ctx *ctx = acrtc->ctx;
> +
> +	adjusted_mode->clock =
> +		clk_round_rate(ctx->ade_pix_clk, mode->clock * 1000) / 1000;
> +	return true;
> +}
> +
> +
>  static void ade_set_pix_clk(struct ade_hw_ctx *ctx,
>  			    struct drm_display_mode *mode,
>  			    struct drm_display_mode *adj_mode)
> @@ -555,6 +568,7 @@ static void ade_crtc_atomic_flush(struct drm_crtc *crtc,
>  static const struct drm_crtc_helper_funcs ade_crtc_helper_funcs = {
>  	.enable		= ade_crtc_enable,
>  	.disable	= ade_crtc_disable,
> +	.mode_fixup	= ade_crtc_mode_fixup,
>  	.mode_set_nofb	= ade_crtc_mode_set_nofb,
>  	.atomic_begin	= ade_crtc_atomic_begin,
>  	.atomic_flush	= ade_crtc_atomic_flush,
John Stultz July 19, 2017, 7:21 p.m. UTC | #2
On Wed, Jul 19, 2017 at 3:16 AM, Jose Abreu <Jose.Abreu@synopsys.com> wrote:
> Hi John,
>
>
> On 18-07-2017 18:59, John Stultz wrote:
>> Currently the hikey dsi logic cannot generate accurate byte
>> clocks values for all pixel clock values. Thus if a mode clock
>> is selected that cannot match the calculated byte clock, the
>> device will boot with a blank screen.
>>
>> This patch uses the new mode_valid callback (many thanks to
>> Jose Abreu for upstreaming it!) to ensure we don't select
>> modes we cannot generate.
>>
>> Also, since the ade crtc code will adjust the mode in mode_set,
>> this patch also adds a mode_fixup callback which we use to make
>> sure we are validating the mode clock that will eventually be
>> used.
>>
>> Many thanks to Jose and Daniel for recent feedback. I think this
>> version is looking much nicer. But I'd still welcome any feedback
>> or suggestions!
>>
>> Cc: Daniel Vetter <daniel.vetter@intel.com>
>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>> Cc: Sean Paul <seanpaul@chromium.org>
>> Cc: David Airlie <airlied@linux.ie>
>> Cc: Rob Clark <robdclark@gmail.com>
>> Cc: Xinliang Liu <xinliang.liu@linaro.org>
>> Cc: Xinliang Liu <z.liuxinliang@hisilicon.com>
>> Cc: Rongrong Zou <zourongrong@gmail.com>
>> Cc: Xinwei Kong <kong.kongxinwei@hisilicon.com>
>> Cc: Chen Feng <puck.chen@hisilicon.com>
>> Cc: Jose Abreu <Jose.Abreu@synopsys.com>
>> Cc: Archit Taneja <architt@codeaurora.org>
>> Cc: dri-devel@lists.freedesktop.org
>> Signed-off-by: John Stultz <john.stultz@linaro.org>
>> ---
>> v2: Reworked to calculate if modeclock matches the phy's
>>     byteclock, rather then using a whitelist of known modes.
>>
>> v3: Reworked to check across all possible crtcs (even though for
>>     us there is only one), and use mode_fixup instead of a custom
>>     function, as suggested by Jose and Daniel.
>> ---
>>  drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c    | 62 +++++++++++++++++++++++++
>>  drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c | 14 ++++++
>>  2 files changed, 76 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
>> index f77dcfa..d7b5820 100644
>> --- a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
>> +++ b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
>> @@ -603,6 +603,67 @@ static void dsi_encoder_enable(struct drm_encoder *encoder)
>>       dsi->enable = true;
>>  }
>>
>> +static enum drm_mode_status dsi_encoder_phy_mode_valid(struct drm_encoder *encoder,
>> +                                     const struct drm_display_mode *mode)
>> +{
>> +     struct dw_dsi *dsi = encoder_to_dsi(encoder);
>> +     struct mipi_phy_params phy;
>> +     u32 bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
>> +     u32 req_kHz, act_kHz, lane_byte_clk_kHz;
>> +
>> +     /* Calculate the lane byte clk using the adjusted mode clk */
>> +     memset(&phy, 0, sizeof(phy));
>> +     req_kHz = mode->clock * bpp / dsi->lanes;
>> +     act_kHz = dsi_calc_phy_rate(req_kHz, &phy);
>> +     lane_byte_clk_kHz = act_kHz / 8;
>> +
>> +     DRM_DEBUG_DRIVER("Checking mode %ix%i-%i@%i clock: %i...",
>> +                     mode->hdisplay, mode->vdisplay, bpp,
>> +                     drm_mode_vrefresh(mode), mode->clock);
>> +
>> +     /*
>> +      * Make sure the adjused mode clock and the lane byte clk
>> +      * have a common denominator base frequency
>> +      */
>> +     if (mode->clock/dsi->lanes == lane_byte_clk_kHz/3) {
>> +             DRM_DEBUG_DRIVER("OK!\n");
>> +             return MODE_OK;
>> +     }
>> +
>> +     DRM_DEBUG_DRIVER("BAD!\n");
>> +     return MODE_BAD;
>> +}
>> +
>> +static enum drm_mode_status dsi_encoder_mode_valid(struct drm_encoder *encoder,
>> +                                     const struct drm_display_mode *mode)
>> +
>> +{
>> +     const struct drm_crtc_helper_funcs *crtc_funcs = NULL;
>> +     struct drm_crtc *crtc = NULL;
>> +     struct drm_display_mode adj_mode;
>> +     int ret;
>
> This int should be an enum drm_mode_status ...
>
>> +
>> +     memcpy(&adj_mode, mode, sizeof(adj_mode));
>
> Maybe you should move this to the loop so that you pass a "clean"
> adjusted mode (i.e. adj_mode == mode) for each crtc. You could
> also use drm_mode_duplicate()/drm_mode_destroy() ...

Ah! Good catch! Thanks for that!

What is the benefit of drm_mode_duplicate over just using memcpy? I
see there's some base.id and head pointers that are kept unique, but
we're not touching those for this case. The extra allocating/freeing
seems a bit needless.


>> +
>> +     /*
>> +      * The crtc might adjust the mode, so go through the
>> +      * possible crtcs (technically just one) and call
>> +      * mode_fixup to figure out the adjusted mode before we
>> +      * validate it.
>> +      */
>> +     drm_for_each_crtc(crtc, encoder->dev) {
>> +             crtc_funcs = crtc->helper_private;
>> +             if (crtc_funcs && crtc_funcs->mode_fixup)
>> +                     ret = crtc_funcs->mode_fixup(crtc, mode,
>> +                                                     &adj_mode);
>
> No return check?

Hrm. Actually, not sure what to do if mode_fixup failed there. I guess
print a warning and validate the unadjusted mode? Other suggestions?

thanks
-john
Jose Abreu July 20, 2017, 9:16 a.m. UTC | #3
On 19-07-2017 20:21, John Stultz wrote:
> On Wed, Jul 19, 2017 at 3:16 AM, Jose Abreu <Jose.Abreu@synopsys.com> wrote:
>> Hi John,
>>
>>
>> On 18-07-2017 18:59, John Stultz wrote:
>>> Currently the hikey dsi logic cannot generate accurate byte
>>> clocks values for all pixel clock values. Thus if a mode clock
>>> is selected that cannot match the calculated byte clock, the
>>> device will boot with a blank screen.
>>>
>>> This patch uses the new mode_valid callback (many thanks to
>>> Jose Abreu for upstreaming it!) to ensure we don't select
>>> modes we cannot generate.
>>>
>>> Also, since the ade crtc code will adjust the mode in mode_set,
>>> this patch also adds a mode_fixup callback which we use to make
>>> sure we are validating the mode clock that will eventually be
>>> used.
>>>
>>> Many thanks to Jose and Daniel for recent feedback. I think this
>>> version is looking much nicer. But I'd still welcome any feedback
>>> or suggestions!
>>>
>>> Cc: Daniel Vetter <daniel.vetter@intel.com>
>>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>>> Cc: Sean Paul <seanpaul@chromium.org>
>>> Cc: David Airlie <airlied@linux.ie>
>>> Cc: Rob Clark <robdclark@gmail.com>
>>> Cc: Xinliang Liu <xinliang.liu@linaro.org>
>>> Cc: Xinliang Liu <z.liuxinliang@hisilicon.com>
>>> Cc: Rongrong Zou <zourongrong@gmail.com>
>>> Cc: Xinwei Kong <kong.kongxinwei@hisilicon.com>
>>> Cc: Chen Feng <puck.chen@hisilicon.com>
>>> Cc: Jose Abreu <Jose.Abreu@synopsys.com>
>>> Cc: Archit Taneja <architt@codeaurora.org>
>>> Cc: dri-devel@lists.freedesktop.org
>>> Signed-off-by: John Stultz <john.stultz@linaro.org>
>>> ---
>>> v2: Reworked to calculate if modeclock matches the phy's
>>>     byteclock, rather then using a whitelist of known modes.
>>>
>>> v3: Reworked to check across all possible crtcs (even though for
>>>     us there is only one), and use mode_fixup instead of a custom
>>>     function, as suggested by Jose and Daniel.
>>> ---
>>>  drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c    | 62 +++++++++++++++++++++++++
>>>  drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c | 14 ++++++
>>>  2 files changed, 76 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
>>> index f77dcfa..d7b5820 100644
>>> --- a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
>>> +++ b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
>>> @@ -603,6 +603,67 @@ static void dsi_encoder_enable(struct drm_encoder *encoder)
>>>       dsi->enable = true;
>>>  }
>>>
>>> +static enum drm_mode_status dsi_encoder_phy_mode_valid(struct drm_encoder *encoder,
>>> +                                     const struct drm_display_mode *mode)
>>> +{
>>> +     struct dw_dsi *dsi = encoder_to_dsi(encoder);
>>> +     struct mipi_phy_params phy;
>>> +     u32 bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
>>> +     u32 req_kHz, act_kHz, lane_byte_clk_kHz;
>>> +
>>> +     /* Calculate the lane byte clk using the adjusted mode clk */
>>> +     memset(&phy, 0, sizeof(phy));
>>> +     req_kHz = mode->clock * bpp / dsi->lanes;
>>> +     act_kHz = dsi_calc_phy_rate(req_kHz, &phy);
>>> +     lane_byte_clk_kHz = act_kHz / 8;
>>> +
>>> +     DRM_DEBUG_DRIVER("Checking mode %ix%i-%i@%i clock: %i...",
>>> +                     mode->hdisplay, mode->vdisplay, bpp,
>>> +                     drm_mode_vrefresh(mode), mode->clock);
>>> +
>>> +     /*
>>> +      * Make sure the adjused mode clock and the lane byte clk
>>> +      * have a common denominator base frequency
>>> +      */
>>> +     if (mode->clock/dsi->lanes == lane_byte_clk_kHz/3) {
>>> +             DRM_DEBUG_DRIVER("OK!\n");
>>> +             return MODE_OK;
>>> +     }
>>> +
>>> +     DRM_DEBUG_DRIVER("BAD!\n");
>>> +     return MODE_BAD;
>>> +}
>>> +
>>> +static enum drm_mode_status dsi_encoder_mode_valid(struct drm_encoder *encoder,
>>> +                                     const struct drm_display_mode *mode)
>>> +
>>> +{
>>> +     const struct drm_crtc_helper_funcs *crtc_funcs = NULL;
>>> +     struct drm_crtc *crtc = NULL;
>>> +     struct drm_display_mode adj_mode;
>>> +     int ret;
>> This int should be an enum drm_mode_status ...
>>
>>> +
>>> +     memcpy(&adj_mode, mode, sizeof(adj_mode));
>> Maybe you should move this to the loop so that you pass a "clean"
>> adjusted mode (i.e. adj_mode == mode) for each crtc. You could
>> also use drm_mode_duplicate()/drm_mode_destroy() ...
> Ah! Good catch! Thanks for that!
>
> What is the benefit of drm_mode_duplicate over just using memcpy? I
> see there's some base.id and head pointers that are kept unique, but
> we're not touching those for this case. The extra allocating/freeing
> seems a bit needless.

Ah, I meant drm_mode_copy(), sorry.

>
>
>>> +
>>> +     /*
>>> +      * The crtc might adjust the mode, so go through the
>>> +      * possible crtcs (technically just one) and call
>>> +      * mode_fixup to figure out the adjusted mode before we
>>> +      * validate it.
>>> +      */
>>> +     drm_for_each_crtc(crtc, encoder->dev) {
>>> +             crtc_funcs = crtc->helper_private;
>>> +             if (crtc_funcs && crtc_funcs->mode_fixup)
>>> +                     ret = crtc_funcs->mode_fixup(crtc, mode,
>>> +                                                     &adj_mode);
>> No return check?
> Hrm. Actually, not sure what to do if mode_fixup failed there. I guess
> print a warning and validate the unadjusted mode? Other suggestions?

Well, from the docs we get for the return value: "True if an
acceptable configuration is possible, false if the modeset
operation should be rejected." So, maybe return immediately
MODE_BAD ?

Best regards,
Jose Miguel Abreu

>
> thanks
> -john
diff mbox

Patch

diff --git a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
index f77dcfa..d7b5820 100644
--- a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
+++ b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
@@ -603,6 +603,67 @@  static void dsi_encoder_enable(struct drm_encoder *encoder)
 	dsi->enable = true;
 }
 
+static enum drm_mode_status dsi_encoder_phy_mode_valid(struct drm_encoder *encoder,
+					const struct drm_display_mode *mode)
+{
+	struct dw_dsi *dsi = encoder_to_dsi(encoder);
+	struct mipi_phy_params phy;
+	u32 bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
+	u32 req_kHz, act_kHz, lane_byte_clk_kHz;
+
+	/* Calculate the lane byte clk using the adjusted mode clk */
+	memset(&phy, 0, sizeof(phy));
+	req_kHz = mode->clock * bpp / dsi->lanes;
+	act_kHz = dsi_calc_phy_rate(req_kHz, &phy);
+	lane_byte_clk_kHz = act_kHz / 8;
+
+	DRM_DEBUG_DRIVER("Checking mode %ix%i-%i@%i clock: %i...",
+			mode->hdisplay, mode->vdisplay, bpp,
+			drm_mode_vrefresh(mode), mode->clock);
+
+	/*
+	 * Make sure the adjused mode clock and the lane byte clk
+	 * have a common denominator base frequency
+	 */
+	if (mode->clock/dsi->lanes == lane_byte_clk_kHz/3) {
+		DRM_DEBUG_DRIVER("OK!\n");
+		return MODE_OK;
+	}
+
+	DRM_DEBUG_DRIVER("BAD!\n");
+	return MODE_BAD;
+}
+
+static enum drm_mode_status dsi_encoder_mode_valid(struct drm_encoder *encoder,
+					const struct drm_display_mode *mode)
+
+{
+	const struct drm_crtc_helper_funcs *crtc_funcs = NULL;
+	struct drm_crtc *crtc = NULL;
+	struct drm_display_mode adj_mode;
+	int ret;
+
+	memcpy(&adj_mode, mode, sizeof(adj_mode));
+
+	/*
+	 * The crtc might adjust the mode, so go through the
+	 * possible crtcs (technically just one) and call
+	 * mode_fixup to figure out the adjusted mode before we
+	 * validate it.
+	 */
+	drm_for_each_crtc(crtc, encoder->dev) {
+		crtc_funcs = crtc->helper_private;
+		if (crtc_funcs && crtc_funcs->mode_fixup)
+			ret = crtc_funcs->mode_fixup(crtc, mode,
+							&adj_mode);
+
+		ret = dsi_encoder_phy_mode_valid(encoder, &adj_mode);
+		if (ret != MODE_OK)
+			return ret;
+	}
+	return MODE_OK;
+}
+
 static void dsi_encoder_mode_set(struct drm_encoder *encoder,
 				 struct drm_display_mode *mode,
 				 struct drm_display_mode *adj_mode)
@@ -622,6 +683,7 @@  static int dsi_encoder_atomic_check(struct drm_encoder *encoder,
 
 static const struct drm_encoder_helper_funcs dw_encoder_helper_funcs = {
 	.atomic_check	= dsi_encoder_atomic_check,
+	.mode_valid	= dsi_encoder_mode_valid,
 	.mode_set	= dsi_encoder_mode_set,
 	.enable		= dsi_encoder_enable,
 	.disable	= dsi_encoder_disable
diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c
index c96c228..dec7f4e 100644
--- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c
+++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c
@@ -178,6 +178,19 @@  static void ade_init(struct ade_hw_ctx *ctx)
 			FRM_END_START_MASK, REG_EFFECTIVE_IN_ADEEN_FRMEND);
 }
 
+static bool ade_crtc_mode_fixup(struct drm_crtc *crtc,
+				const struct drm_display_mode *mode,
+				struct drm_display_mode *adjusted_mode)
+{
+	struct ade_crtc *acrtc = to_ade_crtc(crtc);
+	struct ade_hw_ctx *ctx = acrtc->ctx;
+
+	adjusted_mode->clock =
+		clk_round_rate(ctx->ade_pix_clk, mode->clock * 1000) / 1000;
+	return true;
+}
+
+
 static void ade_set_pix_clk(struct ade_hw_ctx *ctx,
 			    struct drm_display_mode *mode,
 			    struct drm_display_mode *adj_mode)
@@ -555,6 +568,7 @@  static void ade_crtc_atomic_flush(struct drm_crtc *crtc,
 static const struct drm_crtc_helper_funcs ade_crtc_helper_funcs = {
 	.enable		= ade_crtc_enable,
 	.disable	= ade_crtc_disable,
+	.mode_fixup	= ade_crtc_mode_fixup,
 	.mode_set_nofb	= ade_crtc_mode_set_nofb,
 	.atomic_begin	= ade_crtc_atomic_begin,
 	.atomic_flush	= ade_crtc_atomic_flush,