Re: [PATCH 1/3] drm/i915: Add get_config implementation for DSI encoder

Daniel Vetter
2014-07-12T11:58:19Z

On Sat, Jul 12, 2014 at 1:47 PM, Shobhit Kumar <shobhit.kumar@intel.com> wrote:
> Call to vlv_crtc_clock_get is not needed for DSI and was causing dpio
> read WARN dumps as well. Absence of ->get_config was casuing othet WARN
> dumps as well. With this the last of the known WARN dumps for DSI should
> be fixed.
>
> Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
> ---
> drivers/gpu/drm/i915/intel_display.c | 7 +++---
> drivers/gpu/drm/i915/intel_dsi.c | 45 ++++++++++++++++++++++++++++++++++++
> drivers/gpu/drm/i915/intel_dsi.h | 3 +++
> drivers/gpu/drm/i915/intel_dsi_pll.c | 4 +++-
> 4 files changed, 55 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index fe6f1db..3d0ea7c 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -6309,9 +6309,10 @@ static bool i9xx_get_pipe_config(struct intel_crtc *crtc,
>
> if (IS_CHERRYVIEW(dev))
> chv_crtc_clock_get(crtc, pipe_config);
> - else if (IS_VALLEYVIEW(dev))
> - vlv_crtc_clock_get(crtc, pipe_config);
> - else
> + else if (IS_VALLEYVIEW(dev)) {
> + if (!intel_pipe_has_type(&crtc->base, INTEL_OUTPUT_DSI))
> + vlv_crtc_clock_get(crtc, pipe_config);

If I understand the logic correctly we don't even enable the DPLL for
dsi, i.e. bit31 is clear. So instead of this sw-side check (which is
fragile since it depends upon corrected encoder->pipe links in our
data structures) we should instead check bit 31 in vlv_crtc_clock_get
and just bail out without reading out hw settings.

The goal of the hw state cross-check is to check the hw state, so
wherever possible we should rely 100% on available information in the
hw and not on software tracking.

> + } else
> i9xx_crtc_clock_get(crtc, pipe_config);
>
> return true;
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
> index bfcefbf..61da0e5 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -351,9 +351,54 @@ static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,
> static void intel_dsi_get_config(struct intel_encoder *encoder,
> struct intel_crtc_config *pipe_config)
> {
> + struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
> + struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> + u32 dsi_clock, pclk;
> + u32 pll_ctl, pll_div;
> + u32 m = 0, p = 0;
> + int refclk = 25000;
> + int i;
> +
> DRM_DEBUG_KMS("\n");
>
> /* XXX: read flags, set to adjusted_mode */
> + pipe_config->quirks = 1;

Nack. First you need to use one of the symbolic quirk definitions
(there's a bunch of them). Second this needs a comment why exactly we
need the quirk (which really only should be used if there's no way to
read a given piece of state back from the hw).

> +
> + memset(&pipe_config->dpll_hw_state, 0,
> + sizeof(pipe_config->dpll_hw_state));
> +
> + mutex_lock(&dev_priv->dpio_lock);
> + pll_ctl = vlv_cck_read(dev_priv, CCK_REG_DSI_PLL_CONTROL);
> + pll_div = vlv_cck_read(dev_priv, CCK_REG_DSI_PLL_DIVIDER);
> + mutex_unlock(&dev_priv->dpio_lock);
> +
> + pll_ctl &= ~(DSI_PLL_CLK_GATE_DSI0_DSIPLL | DSI_PLL_VCO_EN);
> + pll_ctl = pll_ctl >> (DSI_PLL_P1_POST_DIV_SHIFT - 2);
> +
> + while (pll_ctl) {
> + pll_ctl = pll_ctl >> 1;
> + p++;
> + }
> + p--;
> +
> + for (i = 0; i < num_lfsr_converts; i++) {
> + if (lfsr_converts[i] == pll_div)
> + break;
> + }
> +
> + if (i == num_lfsr_converts) {
> + DRM_ERROR("wrong m_seed programmed\n");
> + return;
> + }
> +
> + m = i + 62;
> +
> + dsi_clock = (m * refclk) / p;
> + pclk = DIV_ROUND_CLOSEST(dsi_clock * intel_dsi->lane_count,
> + pipe_config->pipe_bpp);
> +
> + pipe_config->adjusted_mode.crtc_clock = pclk;
> + pipe_config->port_clock = pclk;
> }
>
> static enum drm_mode_status
> diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
> index 31db33d..e0c16b0 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.h
> +++ b/drivers/gpu/drm/i915/intel_dsi.h
> @@ -130,6 +130,9 @@ static inline struct intel_dsi *enc_to_intel_dsi(struct drm_encoder *encoder)
> return container_of(encoder, struct intel_dsi, base.base);
> }
>
> +extern const u32 lfsr_converts[];
> +extern const int num_lfsr_converts;
> +
> extern void vlv_enable_dsi_pll(struct intel_encoder *encoder);
> extern void vlv_disable_dsi_pll(struct intel_encoder *encoder);
>
> diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c
> index ba79ec1..78449ea 100644
> --- a/drivers/gpu/drm/i915/intel_dsi_pll.c
> +++ b/drivers/gpu/drm/i915/intel_dsi_pll.c
> @@ -43,13 +43,15 @@ struct dsi_mnp {
> u32 dsi_pll_div;
> };
>
> -static const u32 lfsr_converts[] = {
> +const u32 lfsr_converts[] = {
> 426, 469, 234, 373, 442, 221, 110, 311, 411, /* 62 - 70 */
> 461, 486, 243, 377, 188, 350, 175, 343, 427, 213, /* 71 - 80 */
> 106, 53, 282, 397, 354, 227, 113, 56, 284, 142, /* 81 - 90 */
> 71, 35 /* 91 - 92 */
> };

Optional bikeshed: I'd extract the dsi pll read-out code into a helper
function so that all the pll code is in this file and we don't need to
export internal details. The get_hw_state function in intel_dsi.c
would then use that to compute pclk and just store that at the right
places in the pipe config.
-Daniel

>
> +const int num_lfsr_converts = sizeof(lfsr_converts) / sizeof(lfsr_converts[0]);
> +
> #ifdef DSI_CLK_FROM_RR
>
> static u32 dsi_rr_formula(const struct drm_display_mode *mode,
> --
> 1.9.1
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch