[Intel-gfx] [PATCH v6 7/8] drm/i915: BDW clock change support
Jani Nikula
jani.nikula at linux.intel.com
Tue Jun 16 06:01:16 PDT 2015
On Wed, 03 Jun 2015, Mika Kahola <mika.kahola at intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> 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 at linux.intel.com>
> Signed-off-by: Mika Kahola <mika.kahola at intel.com>
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.
BR,
Jani.
>
> Author: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
> 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
>
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--
Jani Nikula, Intel Open Source Technology Center
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