Re: [PATCH v6 7/8] drm/i915: BDW clock change support

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On Tue, 16 Jun 2015, Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> wrote:
> On Wed, 03 Jun 2015, Mika Kahola <mika.kahola@xxxxxxxxx> wrote:
>> From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>>
>> Add support for changing cdclk frequency during runtime on BDW. The
>> procedure is quite a bit different on BDW from the one on HSW, so
>> add a separate function for it.
>>
>> Also with IPS enabled the actual pixel rate mustn't exceed 95% of cdclk,
>> so take that into account when computing the max pixel rate.
>>
>> v2: Grab rps.hw_lock around sandybridge_pcode_write()
>> v3: Rebase due to power well vs. .global_resources() reordering
>> v4: Rebased to the latest
>> v5: Rebased to the latest
>> v6: Patch order shuffle so that Broadwell CD clock change is
>>     applied before the patch for Haswell CD clock change
>> v7: Fix for patch style problems
>>
>> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>> Signed-off-by: Mika Kahola <mika.kahola@xxxxxxxxx>
>
> This patch hard hangs my BDW NUC at boot when both DP and HDMI are
> connected. Either DP or HDMI alone are good, same with hotplugging the
> other afterwards. Booting to grub with both connected, and unplugging
> HDMI before loading the kernel also reproduces the issue.
>
> It looks like the problem boils down to the BIOS setting up a smaller
> resolution on the DP display when both are connected, and this patch
> fails to cope with that on i915 load.

By "this patch" I obviously refer to

commit b432e5cfd5e92127ad2dd83bfc3083f1dbce43fb
Author: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Date:   Wed Jun 3 15:45:13 2015 +0300

    drm/i915: BDW clock change support

and everything works for the commit before that.

BR,
Jani.





>
> BR,
> Jani.
>
>
>
>>
>> Author:    Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>> ---
>>  drivers/gpu/drm/i915/i915_reg.h      |   2 +
>>  drivers/gpu/drm/i915/intel_display.c | 216 +++++++++++++++++++++++++++++++++--
>>  2 files changed, 208 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
>> index 7213224..0f72c0e 100644
>> --- a/drivers/gpu/drm/i915/i915_reg.h
>> +++ b/drivers/gpu/drm/i915/i915_reg.h
>> @@ -6705,6 +6705,7 @@ enum skl_disp_power_wells {
>>  #define	  GEN6_PCODE_READ_RC6VIDS		0x5
>>  #define     GEN6_ENCODE_RC6_VID(mv)		(((mv) - 245) / 5)
>>  #define     GEN6_DECODE_RC6_VID(vids)		(((vids) * 5) + 245)
>> +#define   BDW_PCODE_DISPLAY_FREQ_CHANGE_REQ	0x18
>>  #define   GEN9_PCODE_READ_MEM_LATENCY		0x6
>>  #define     GEN9_MEM_LATENCY_LEVEL_MASK		0xFF
>>  #define     GEN9_MEM_LATENCY_LEVEL_1_5_SHIFT	8
>> @@ -7170,6 +7171,7 @@ enum skl_disp_power_wells {
>>  #define  LCPLL_CLK_FREQ_337_5_BDW	(2<<26)
>>  #define  LCPLL_CLK_FREQ_675_BDW		(3<<26)
>>  #define  LCPLL_CD_CLOCK_DISABLE		(1<<25)
>> +#define  LCPLL_ROOT_CD_CLOCK_DISABLE	(1<<24)
>>  #define  LCPLL_CD2X_CLOCK_DISABLE	(1<<23)
>>  #define  LCPLL_POWER_DOWN_ALLOW		(1<<22)
>>  #define  LCPLL_CD_SOURCE_FCLK		(1<<21)
>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>> index c3f01aa..b1e2069 100644
>> --- a/drivers/gpu/drm/i915/intel_display.c
>> +++ b/drivers/gpu/drm/i915/intel_display.c
>> @@ -5751,7 +5751,22 @@ static void intel_update_max_cdclk(struct drm_device *dev)
>>  {
>>  	struct drm_i915_private *dev_priv = dev->dev_private;
>>  
>> -	if (IS_VALLEYVIEW(dev)) {
>> +	if (IS_BROADWELL(dev))  {
>> +		/*
>> +		 * FIXME with extra cooling we can allow
>> +		 * 540 MHz for ULX and 675 Mhz for ULT.
>> +		 * How can we know if extra cooling is
>> +		 * available? PCI ID, VTB, something else?
>> +		 */
>> +		if (I915_READ(FUSE_STRAP) & HSW_CDCLK_LIMIT)
>> +			dev_priv->max_cdclk_freq = 450000;
>> +		else if (IS_BDW_ULX(dev))
>> +			dev_priv->max_cdclk_freq = 450000;
>> +		else if (IS_BDW_ULT(dev))
>> +			dev_priv->max_cdclk_freq = 540000;
>> +		else
>> +			dev_priv->max_cdclk_freq = 675000;
>> +	} else if (IS_VALLEYVIEW(dev)) {
>>  		dev_priv->max_cdclk_freq = 400000;
>>  	} else {
>>  		/* otherwise assume cdclk is fixed */
>> @@ -6621,13 +6636,11 @@ static bool pipe_config_supports_ips(struct drm_i915_private *dev_priv,
>>  		return true;
>>  
>>  	/*
>> -	 * FIXME if we compare against max we should then
>> -	 * increase the cdclk frequency when the current
>> -	 * value is too low. The other option is to compare
>> -	 * against the cdclk frequency we're going have post
>> -	 * modeset (ie. one we computed using other constraints).
>> -	 * Need to measure whether using a lower cdclk w/o IPS
>> -	 * is better or worse than a higher cdclk w/ IPS.
>> +	 * We compare against max which means we must take
>> +	 * the increased cdclk requirement into account when
>> +	 * calculating the new cdclk.
>> +	 *
>> +	 * Should measure whether using a lower cdclk w/o IPS
>>  	 */
>>  	return ilk_pipe_pixel_rate(pipe_config) <=
>>  		dev_priv->max_cdclk_freq * 95 / 100;
>> @@ -9608,6 +9621,182 @@ static void broxton_modeset_global_resources(struct drm_atomic_state *old_state)
>>  		broxton_set_cdclk(dev, req_cdclk);
>>  }
>>  
>> +/* compute the max rate for new configuration */
>> +static int ilk_max_pixel_rate(struct drm_i915_private *dev_priv)
>> +{
>> +	struct drm_device *dev = dev_priv->dev;
>> +	struct intel_crtc *intel_crtc;
>> +	struct drm_crtc *crtc;
>> +	int max_pixel_rate = 0;
>> +	int pixel_rate;
>> +
>> +	for_each_crtc(dev, crtc) {
>> +		if (!crtc->state->enable)
>> +			continue;
>> +
>> +		intel_crtc = to_intel_crtc(crtc);
>> +		pixel_rate = ilk_pipe_pixel_rate(intel_crtc->config);
>> +
>> +		/* pixel rate mustn't exceed 95% of cdclk with IPS on BDW */
>> +		if (IS_BROADWELL(dev) && intel_crtc->config->ips_enabled)
>> +			pixel_rate = DIV_ROUND_UP(pixel_rate * 100, 95);
>> +
>> +		max_pixel_rate = max(max_pixel_rate, pixel_rate);
>> +	}
>> +
>> +	return max_pixel_rate;
>> +}
>> +
>> +static void broadwell_set_cdclk(struct drm_device *dev, int cdclk)
>> +{
>> +	struct drm_i915_private *dev_priv = dev->dev_private;
>> +	uint32_t val, data;
>> +	int ret;
>> +
>> +	if (WARN((I915_READ(LCPLL_CTL) &
>> +		  (LCPLL_PLL_DISABLE | LCPLL_PLL_LOCK |
>> +		   LCPLL_CD_CLOCK_DISABLE | LCPLL_ROOT_CD_CLOCK_DISABLE |
>> +		   LCPLL_CD2X_CLOCK_DISABLE | LCPLL_POWER_DOWN_ALLOW |
>> +		   LCPLL_CD_SOURCE_FCLK)) != LCPLL_PLL_LOCK,
>> +		 "trying to change cdclk frequency with cdclk not enabled\n"))
>> +		return;
>> +
>> +	mutex_lock(&dev_priv->rps.hw_lock);
>> +	ret = sandybridge_pcode_write(dev_priv,
>> +				      BDW_PCODE_DISPLAY_FREQ_CHANGE_REQ, 0x0);
>> +	mutex_unlock(&dev_priv->rps.hw_lock);
>> +	if (ret) {
>> +		DRM_ERROR("failed to inform pcode about cdclk change\n");
>> +		return;
>> +	}
>> +
>> +	val = I915_READ(LCPLL_CTL);
>> +	val |= LCPLL_CD_SOURCE_FCLK;
>> +	I915_WRITE(LCPLL_CTL, val);
>> +
>> +	if (wait_for_atomic_us(I915_READ(LCPLL_CTL) &
>> +			       LCPLL_CD_SOURCE_FCLK_DONE, 1))
>> +		DRM_ERROR("Switching to FCLK failed\n");
>> +
>> +	val = I915_READ(LCPLL_CTL);
>> +	val &= ~LCPLL_CLK_FREQ_MASK;
>> +
>> +	switch (cdclk) {
>> +	case 450000:
>> +		val |= LCPLL_CLK_FREQ_450;
>> +		data = 0;
>> +		break;
>> +	case 540000:
>> +		val |= LCPLL_CLK_FREQ_54O_BDW;
>> +		data = 1;
>> +		break;
>> +	case 337500:
>> +		val |= LCPLL_CLK_FREQ_337_5_BDW;
>> +		data = 2;
>> +		break;
>> +	case 675000:
>> +		val |= LCPLL_CLK_FREQ_675_BDW;
>> +		data = 3;
>> +		break;
>> +	default:
>> +		WARN(1, "invalid cdclk frequency\n");
>> +		return;
>> +	}
>> +
>> +	I915_WRITE(LCPLL_CTL, val);
>> +
>> +	val = I915_READ(LCPLL_CTL);
>> +	val &= ~LCPLL_CD_SOURCE_FCLK;
>> +	I915_WRITE(LCPLL_CTL, val);
>> +
>> +	if (wait_for_atomic_us((I915_READ(LCPLL_CTL) &
>> +				LCPLL_CD_SOURCE_FCLK_DONE) == 0, 1))
>> +		DRM_ERROR("Switching back to LCPLL failed\n");
>> +
>> +	mutex_lock(&dev_priv->rps.hw_lock);
>> +	sandybridge_pcode_write(dev_priv, HSW_PCODE_DE_WRITE_FREQ_REQ, data);
>> +	mutex_unlock(&dev_priv->rps.hw_lock);
>> +
>> +	intel_update_cdclk(dev);
>> +
>> +	WARN(cdclk != dev_priv->cdclk_freq,
>> +	     "cdclk requested %d kHz but got %d kHz\n",
>> +	     cdclk, dev_priv->cdclk_freq);
>> +}
>> +
>> +static int broadwell_calc_cdclk(struct drm_i915_private *dev_priv,
>> +			      int max_pixel_rate)
>> +{
>> +	int cdclk;
>> +
>> +	/*
>> +	 * FIXME should also account for plane ratio
>> +	 * once 64bpp pixel formats are supported.
>> +	 */
>> +	if (max_pixel_rate > 540000)
>> +		cdclk = 675000;
>> +	else if (max_pixel_rate > 450000)
>> +		cdclk = 540000;
>> +	else if (max_pixel_rate > 337500)
>> +		cdclk = 450000;
>> +	else
>> +		cdclk = 337500;
>> +
>> +	/*
>> +	 * FIXME move the cdclk caclulation to
>> +	 * compute_config() so we can fail gracegully.
>> +	 */
>> +	if (cdclk > dev_priv->max_cdclk_freq) {
>> +		DRM_ERROR("requested cdclk (%d kHz) exceeds max (%d kHz)\n",
>> +			  cdclk, dev_priv->max_cdclk_freq);
>> +		cdclk = dev_priv->max_cdclk_freq;
>> +	}
>> +
>> +	return cdclk;
>> +}
>> +
>> +static int broadwell_modeset_global_pipes(struct drm_atomic_state *state)
>> +{
>> +	struct drm_i915_private *dev_priv = to_i915(state->dev);
>> +	struct drm_crtc *crtc;
>> +	struct drm_crtc_state *crtc_state;
>> +	int max_pixclk = ilk_max_pixel_rate(dev_priv);
>> +	int cdclk, i;
>> +
>> +	cdclk = broadwell_calc_cdclk(dev_priv, max_pixclk);
>> +
>> +	if (cdclk == dev_priv->cdclk_freq)
>> +		return 0;
>> +
>> +	/* add all active pipes to the state */
>> +	for_each_crtc(state->dev, crtc) {
>> +		if (!crtc->state->enable)
>> +			continue;
>> +
>> +		crtc_state = drm_atomic_get_crtc_state(state, crtc);
>> +		if (IS_ERR(crtc_state))
>> +			return PTR_ERR(crtc_state);
>> +	}
>> +
>> +	/* disable/enable all currently active pipes while we change cdclk */
>> +	for_each_crtc_in_state(state, crtc, crtc_state, i)
>> +		if (crtc_state->enable)
>> +			crtc_state->mode_changed = true;
>> +
>> +	return 0;
>> +}
>> +
>> +static void broadwell_modeset_global_resources(struct drm_atomic_state *state)
>> +{
>> +	struct drm_device *dev = state->dev;
>> +	struct drm_i915_private *dev_priv = dev->dev_private;
>> +	int max_pixel_rate = ilk_max_pixel_rate(dev_priv);
>> +	int req_cdclk = broadwell_calc_cdclk(dev_priv, max_pixel_rate);
>> +
>> +	if (req_cdclk != dev_priv->cdclk_freq)
>> +		broadwell_set_cdclk(dev, req_cdclk);
>> +}
>> +
>>  static int haswell_crtc_compute_clock(struct intel_crtc *crtc,
>>  				      struct intel_crtc_state *crtc_state)
>>  {
>> @@ -12788,8 +12977,12 @@ static int __intel_set_mode_checks(struct drm_atomic_state *state)
>>  	 * mode set on this crtc.  For other crtcs we need to use the
>>  	 * adjusted_mode bits in the crtc directly.
>>  	 */
>> -	if (IS_VALLEYVIEW(dev) || IS_BROXTON(dev)) {
>> -		ret = valleyview_modeset_global_pipes(state);
>> +	if (IS_VALLEYVIEW(dev) || IS_BROXTON(dev) || IS_BROADWELL(dev)) {
>> +		if (IS_VALLEYVIEW(dev) || IS_BROXTON(dev))
>> +			ret = valleyview_modeset_global_pipes(state);
>> +		else
>> +			ret = broadwell_modeset_global_pipes(state);
>> +
>>  		if (ret)
>>  			return ret;
>>  	}
>> @@ -14677,6 +14870,9 @@ static void intel_init_display(struct drm_device *dev)
>>  		dev_priv->display.fdi_link_train = ivb_manual_fdi_link_train;
>>  	} else if (IS_HASWELL(dev) || IS_BROADWELL(dev)) {
>>  		dev_priv->display.fdi_link_train = hsw_fdi_link_train;
>> +		if (IS_BROADWELL(dev))
>> +			dev_priv->display.modeset_global_resources =
>> +				broadwell_modeset_global_resources;
>>  	} else if (IS_VALLEYVIEW(dev)) {
>>  		dev_priv->display.modeset_global_resources =
>>  			valleyview_modeset_global_resources;
>> -- 
>> 1.9.1
>>
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> -- 
> Jani Nikula, Intel Open Source Technology Center

-- 
Jani Nikula, Intel Open Source Technology Center
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