[RFC] drm/i915: adding state checker for gamma lut values

Jani Nikula jani.nikula at intel.com
Wed Mar 20 12:41:24 UTC 2019


On Wed, 20 Mar 2019, "Sharma, Swati2" <swati2.sharma at intel.com> wrote:
> On 15-Mar-19 3:17 PM, Nikula, Jani wrote:
>> On Fri, 15 Mar 2019, swati2.sharma at intel.com wrote:
>>> From: Swati Sharma <swati2.sharma at intel.com>
>>>
>>> Added state checker to validate gamma_lut values. This
>>> reads hardware state, and compares the originally requested
>>> state to the state read from hardware.
>>>
>>> This implementation can be used for Gen9+ platforms,
>>> I haven't implemented it for legacy platforms. Just want to get
>>> feedback if this is the right approach to follow.
>>>
>>> Also, inverse function of drm_color_lut_extract is missing
>>> to convert hardware read values back to user values.
>>> Thinking for that. I have added all "TODOs" and "Placeholders".
>>>
>>> Another approach:
>>> Storing "word" to be written into hardware in dev_priv and
>>> instead of comparing blob, comparing "word"? In dev_priv,
>>> only pointer will be there (something like *gamma_word).
>> You can't store it in dev_priv because it's crtc state specific
>> data. Even if stored in crtc state, the approach doesn't help the
>> initial hw state readout and takeover.
>>
>> Please use intel-gfx mailing list for i915 patches.
>>
>>> For this too, I will send a patch to make it more clear.
>>>
>>> Signed-off-by: Swati Sharma <swati2.sharma at intel.com>
>>> ---
>>>   drivers/gpu/drm/i915/i915_drv.h      |   1 +
>>>   drivers/gpu/drm/i915/intel_color.c   | 127 +++++++++++++++++++++++++++++++++--
>>>   drivers/gpu/drm/i915/intel_display.c |  50 ++++++++++++++
>>>   drivers/gpu/drm/i915/intel_drv.h     |   1 +
>>>   4 files changed, 173 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>>> index c4ffe19..b41bfaa 100644
>>> --- a/drivers/gpu/drm/i915/i915_drv.h
>>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>>> @@ -334,6 +334,7 @@ struct drm_i915_display_funcs {
>>>   	 * involved with the same commit.
>>>   	 */
>>>   	void (*load_luts)(const struct intel_crtc_state *crtc_state);
>>> +	void (*get_config)(struct intel_crtc_state *crtc_state);
>> The name is too generic.
>>
>>>   };
>>>   
>>>   #define CSR_VERSION(major, minor)	((major) << 16 | (minor))
>>> diff --git a/drivers/gpu/drm/i915/intel_color.c b/drivers/gpu/drm/i915/intel_color.c
>>> index da7a07d..a515e9f 100644
>>> --- a/drivers/gpu/drm/i915/intel_color.c
>>> +++ b/drivers/gpu/drm/i915/intel_color.c
>>> @@ -74,6 +74,11 @@
>>>   #define ILK_CSC_COEFF_1_0		\
>>>   	((7 << 12) | ILK_CSC_COEFF_FP(CTM_COEFF_1_0, 8))
>>>   
>>> +/* Mask to extract RGB values from registers */
>>> +#define COLOR_BLUE_MASK         0x000003FF              /* 9:0 */
>>> +#define COLOR_GREEN_MASK        0x000FFC00              /* 19:10 */
>>> +#define COLOR_RED_MASK          0x3FF00000              /* 29:20 */
>> These belong in i915_reg.h, and you need platform specific shifts and
>> masks. The code that writes the registers seems to use magic numbers...
>>
>>> +
>>>   static bool lut_is_legacy(const struct drm_property_blob *lut)
>>>   {
>>>   	return drm_color_lut_size(lut) == LEGACY_LUT_LENGTH;
>>> @@ -672,6 +677,97 @@ static void cherryview_load_luts(const struct intel_crtc_state *crtc_state)
>>>   	i9xx_load_luts_internal(crtc_state, NULL);
>>>   }
>>>   
>>> +static void bdw_get_gamma_config(struct intel_crtc_state *crtc_state, u32 offset)
>>> +{
>>> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
>>> +	struct drm_device *dev = crtc->base.dev;
>>> +	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
>>> +	u32 i, tmp, lut_size = INTEL_INFO(dev_priv)->color.gamma_lut_size;
>>> +	enum pipe pipe = crtc->pipe;
>>> +	struct drm_property_blob *blob = NULL;
>>> +	struct drm_color_lut *blob_data;
>>> +
>>> +	WARN_ON(offset & ~PAL_PREC_INDEX_VALUE_MASK);
>>> +
>>> +	I915_WRITE(PREC_PAL_INDEX(pipe),
>>> +			(offset ? PAL_PREC_SPLIT_MODE : 0) |
>>> +			PAL_PREC_AUTO_INCREMENT |
>>> +			offset);
>>> +
>>> +	blob = drm_property_create_blob(dev,
>>> +			sizeof(struct drm_color_lut) * lut_size,
>>> +			NULL);
>>> +	if (IS_ERR(blob))
>>> +		return;
>>> +
>>> +	blob_data = blob->data;
>>> +
>>> +	for (i = 0; i < lut_size; i++) {
>>> +		tmp = I915_READ(PREC_PAL_DATA(pipe));
>>> +		/*
>>> +		 * TODO: convert RGB value read from register into corresponding user value using
>>> +		 * some wrapper like drm_color_lut_put() (or) intel_color_lut_put() so that it
>>> +		 * can be compared later.
>>> +		 */
>> Yeah, you'll need this.
> Can you please help in this?

Something like this:

/* convert hw value with given bit_precision to lut property val */
u32 drm_color_lut_pack(u32 val, u32 bit_precision)
{
	u32 max = 0xffff >> (16 - bit_precision);

	val = clamp_val(val, 0, max);

	if (bit_precision < 16)
		val <<= 16 - bit_precision;

	return val;
}

/* compare two lut property values with given bit_precision */
bool drm_color_lut_match(u32 a, u32 b, u32 bit_precision)
{
	u32 err = 0xffff >> bit_precision;

	return abs((long)a - b) <= err;
}

I didn't double check the math, but it's probably close enough for
starters. ;)



BR,
Jani.




>>
>>> +		blob_data[i].red = (tmp & COLOR_RED_MASK) >> 20;
>>> +		blob_data[i].green = (tmp & COLOR_GREEN_MASK) >> 10;
>>> +		blob_data[i].blue = tmp & COLOR_BLUE_MASK;
>>> +	}
>>> +
>>> +	I915_WRITE(PREC_PAL_INDEX(pipe), 0);
>>> +
>>> +	crtc_state->base.gamma_lut = blob;
>>> +}
>>> +
>>> +static void i9xx_get_config(struct intel_crtc_state *crtc_state)
>> Please include (de)gamma or color in the function names.
>>
>>> +{
>>> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
>>> +	struct drm_device *dev = crtc->base.dev;
>>> +	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
>>> +	u32 i, tmp;
>>> +	enum pipe pipe = crtc->pipe;
>>> +	struct drm_property_blob *blob = NULL;
>>> +	struct drm_color_lut *blob_data;
>>> +
>>> +	blob = drm_property_create_blob(dev,
>>> +					sizeof(struct drm_color_lut) * 256,
>>> +					NULL);
>>> +	if (IS_ERR(blob))
>>> +		return;
>>> +
>>> +	blob_data = blob->data;
>>> +
>>> +	for (i = 0; i < 256; i++) {
>>> +		if (HAS_GMCH(dev_priv))
>>> +			tmp = I915_READ(PALETTE(pipe, i));
>>> +		else
>>> +			tmp = I915_READ(LGC_PALETTE(pipe, i));
>>> +		/*
>>> +		 * TODO: convert RGB value read from register into corresponding user value using
>>> +		 * some wrapper like drm_color_lut_put() (or) intel_color_lut_put() so that it
>>> +		 * can be compared later.
>>> +		 */
>>> +		blob_data[i].red = (tmp & COLOR_RED_MASK) >> 20;
>>> +		blob_data[i].green = (tmp & COLOR_GREEN_MASK) >> 10;
>>> +		blob_data[i].blue = (tmp & COLOR_BLUE_MASK);
>>> +	}
>>> +
>>> +	crtc_state->base.gamma_lut = blob;
>>> +}
>>> +
>>> +static void icl_get_config(struct intel_crtc_state *crtc_state)
>>> +{
>>> +	/*
>>> +	 * TODO: placeholder for degamma validation
>>> +	 * glk_get_degamma_config(crtc_state, 0);
>>> +	 */
>>> +
>>> +	if (crtc_state_is_legacy_gamma(crtc_state))
>>> +		i9xx_get_config(crtc_state);
>>> +	else
>>> +		bdw_get_gamma_config(crtc_state, 0);
>>> +}
>>> +
>>>   void intel_color_load_luts(const struct intel_crtc_state *crtc_state)
>>>   {
>>>   	struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);
>>> @@ -679,6 +775,13 @@ void intel_color_load_luts(const struct intel_crtc_state *crtc_state)
>>>   	dev_priv->display.load_luts(crtc_state);
>>>   }
>>>   
>>> +void intel_color_get_config(struct intel_crtc_state *crtc_state)
>>> +{
>>> +	struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);
>>> +
>>> +	dev_priv->display.get_config(crtc_state);
>> This will oops on platforms where you haven't implemented it yet.
>>
>>> +}
>>> +
>>>   void intel_color_commit(const struct intel_crtc_state *crtc_state)
>>>   {
>>>   	struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);
>>> @@ -833,22 +936,34 @@ void intel_color_init(struct intel_crtc *crtc)
>>>   
>>>   	drm_mode_crtc_set_gamma_size(&crtc->base, 256);
>>>   
>>> +	/*
>>> +	 * TODO: In the following if ladder, kept placeholders
>>> +	 * for extending lut validation for legacy platforms.
>>> +	 */
>> I think adding the placeholder comments is too messy.
>>
>>>   	if (HAS_GMCH(dev_priv)) {
>>> -		if (IS_CHERRYVIEW(dev_priv))
>>> +		if (IS_CHERRYVIEW(dev_priv)) {
>>>   			dev_priv->display.load_luts = cherryview_load_luts;
>>> -		else
>>> +			 /* dev_priv->display.get_config = cherryview_get_config; */
>>> +		} else {
>>>   			dev_priv->display.load_luts = i9xx_load_luts;
>>> +			dev_priv->display.get_config = i9xx_get_config;
>>> +		}
>>>   
>>>   		dev_priv->display.color_commit = i9xx_color_commit;
>>>   	} else {
>>> -		if (IS_ICELAKE(dev_priv))
>>> +		if (IS_ICELAKE(dev_priv)) {
>>>   			dev_priv->display.load_luts = icl_load_luts;
>>> -		else if (IS_CANNONLAKE(dev_priv) || IS_GEMINILAKE(dev_priv))
>>> +			dev_priv->display.get_config = icl_get_config;
>>> +		} else if (IS_CANNONLAKE(dev_priv) || IS_GEMINILAKE(dev_priv)) {
>>>   			dev_priv->display.load_luts = glk_load_luts;
>>> -		else if (INTEL_GEN(dev_priv) >= 9 || IS_BROADWELL(dev_priv))
>>> +			/* dev_priv->display.get_config = glk_get_config; */
>>> +		} else if (INTEL_GEN(dev_priv) >= 9 || IS_BROADWELL(dev_priv)) {
>>>   			dev_priv->display.load_luts = broadwell_load_luts;
>>> -		else
>>> +			/* dev_priv->display.get_config = broadwell_get_config; */
>>> +		} else {
>>>   			dev_priv->display.load_luts = i9xx_load_luts;
>>> +			dev_priv->display.get_config = i9xx_get_config;
>>> +		}
>>>   
>>>   		if (INTEL_GEN(dev_priv) >= 9)
>>>   			dev_priv->display.color_commit = skl_color_commit;
>>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>>> index 963b4bd..165d797 100644
>>> --- a/drivers/gpu/drm/i915/intel_display.c
>>> +++ b/drivers/gpu/drm/i915/intel_display.c
>>> @@ -8212,6 +8212,11 @@ static bool i9xx_get_pipe_config(struct intel_crtc *crtc,
>>>   
>>>   	i9xx_get_pipe_color_config(pipe_config);
>>>   
>>> +	/*
>>> +	 * TODO: Yet to implement for legacy platforms
>>> +	 * intel_color_get_config(pipe_config);
>>> +	 */
>>> +
>> I'm not sure about adding these comments either.
>>
>>>   	if (INTEL_GEN(dev_priv) < 4)
>>>   		pipe_config->double_wide = tmp & PIPECONF_DOUBLE_WIDE;
>>>   
>>> @@ -9284,6 +9289,11 @@ static bool ironlake_get_pipe_config(struct intel_crtc *crtc,
>>>   
>>>   	i9xx_get_pipe_color_config(pipe_config);
>>>   
>>> +	/*
>>> +	 * TODO: Yet to implement for legacy platforms
>>> +	 * intel_color_get_config(pipe_config);
>>> +	 */
>>> +
>>>   	if (I915_READ(PCH_TRANSCONF(crtc->pipe)) & TRANS_ENABLE) {
>>>   		struct intel_shared_dpll *pll;
>>>   		enum intel_dpll_id pll_id;
>>> @@ -9932,6 +9942,8 @@ static bool haswell_get_pipe_config(struct intel_crtc *crtc,
>>>   		i9xx_get_pipe_color_config(pipe_config);
>>>   	}
>>>   
>>> +	intel_color_get_config(pipe_config);
>>> +
>>>   	power_domain = POWER_DOMAIN_PIPE_PANEL_FITTER(crtc->pipe);
>>>   	if (intel_display_power_get_if_enabled(dev_priv, power_domain)) {
>>>   		WARN_ON(power_domain_mask & BIT_ULL(power_domain));
>>> @@ -11990,6 +12002,34 @@ static bool fastboot_enabled(struct drm_i915_private *dev_priv)
>>>   	return false;
>>>   }
>>>   
>>> +static bool intel_compare_blob(struct drm_property_blob *blob1,
>>> +			       struct drm_property_blob *blob2)
>>> +{
>>> +	struct drm_color_lut *sw_lut = blob1->data;
>>> +	struct drm_color_lut *hw_lut = blob2->data;
>>> +	int sw_lut_size, hw_lut_size;
>>> +	int i;
>>> +
>>> +	sw_lut_size = drm_color_lut_size(blob1);
>>> +	hw_lut_size = drm_color_lut_size(blob2);
>>> +
>>> +	if (sw_lut_size != hw_lut_size) {
>>> +		DRM_DEBUG_KMS("Invalid LUT size; got %d, expected %d\n", hw_lut_size, sw_lut_size);
>> Please don't add these debug logs here. Instead, add a separate function
>> to log errors at the higher level. Contrast PIPE_CONF_CHECK_INFOFRAME()
>> and pipe_config_infoframe_err(). That can come as a follow-up
>> improvement, but the debug logs here are unnecessary.
>>
>>> +		return false;
>>> +	}
>>> +
>>> +	for (i = 0; i < sw_lut_size; i++) {
>>> +		if (hw_lut[i].red != sw_lut[i].red ||
>>> +		    hw_lut[i].blue != sw_lut[i].blue ||
>>> +		    hw_lut[i].green != sw_lut[i].green) {
>>> +			DRM_DEBUG_KMS("Invalid LUT value; sw_lut value doesn't match hw_lut value\n");
>>> +			return false;
>>> +		}
>>> +	}
>>> +
>>> +	return true;
>>> +}
>>> +
>> I'd put this in intel_color.c and name it properly. You can't use it to
>> compare random blobs, and the comparison needs to take platform specific
>> bit precision of the readout into account.
>>
>> The blobs may be NULL.
>>
>>>   static bool
>>>   intel_pipe_config_compare(struct drm_i915_private *dev_priv,
>>>   			  struct intel_crtc_state *current_config,
>>> @@ -12148,6 +12188,14 @@ static bool fastboot_enabled(struct drm_i915_private *dev_priv)
>>>   	} \
>>>   } while (0)
>>>   
>>> +#define PIPE_CONF_CHECK_BLOB(name) do { \
>> CHECK_LUT or CHECK_COLOR_LUT or something, not just CHECK_BLOB.
>>
>>> +	if (!intel_compare_blob(current_config->name, pipe_config->name)) { \
>>> +		pipe_config_err(adjust, __stringify(name), \
>>> +				"hw_state doesn't match sw_state\n"); \
>>> +		ret = false; \
>>> +	} \
>>> +} while (0)
>>> +
>>>   #define PIPE_CONF_QUIRK(quirk) \
>>>   	((current_config->quirks | pipe_config->quirks) & (quirk))
>>>   
>>> @@ -12287,6 +12335,8 @@ static bool fastboot_enabled(struct drm_i915_private *dev_priv)
>>>   	PIPE_CONF_CHECK_INFOFRAME(spd);
>>>   	PIPE_CONF_CHECK_INFOFRAME(hdmi);
>>>   
>>> +	PIPE_CONF_CHECK_BLOB(base.gamma_lut);
>>> +
>>>   #undef PIPE_CONF_CHECK_X
>>>   #undef PIPE_CONF_CHECK_I
>>>   #undef PIPE_CONF_CHECK_BOOL
>>> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>>> index 40ebc94..a6acd9b 100644
>>> --- a/drivers/gpu/drm/i915/intel_drv.h
>>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>>> @@ -2512,6 +2512,7 @@ int intel_plane_atomic_check_with_state(const struct intel_crtc_state *old_crtc_
>>>   int intel_color_check(struct intel_crtc_state *crtc_state);
>>>   void intel_color_commit(const struct intel_crtc_state *crtc_state);
>>>   void intel_color_load_luts(const struct intel_crtc_state *crtc_state);
>>> +void intel_color_get_config(struct intel_crtc_state *crtc_state);
>>>   
>>>   /* intel_lspcon.c */
>>>   bool lspcon_init(struct intel_digital_port *intel_dig_port);

-- 
Jani Nikula, Intel Open Source Graphics Center


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