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

["Kumar, Shobhit" <shobhit.kumar@intel.com>]

On 7/12/2014 5:28 PM, Daniel Vetter wrote:
> 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.

Yeah, sounds better will do this.

>
> 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.

Got it.

>
>> +       } 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).

Okay, in MIPI we have sync events going as short packets. In that case I 
think it should be okay to use PIPE_CONFIG_QUIRK_MODE_SYNC_FLAGS ?

>
>> +
>> +       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.

Yeah will correct this as well.

Regards
Shobhit