Hi,
On 07/09/2018 08:14 PM, Ville Syrjälä wrote:
On Sat, Jul 07, 2018 at 08:32:16AM +0200, Hans de Goede wrote:
<snip>
Any kind of hack that involves reading out the hardware state should go into something like intel_sanitize_encoder(). Actually by that time we have already read out the hw state, so it shouldn't require any modifications to the existing dsi code itself.
I do not think that intel_sanitize encoder is the right place to do this:
- I don't want to modify the read-back state, I want to modify our calculated "new/ideal" state to match the read-back state
I wasn't suggesting that. What I meant is that you already have the state there to look so you don't have to hack the readout functions to function without a state being around.
That said, we do already have intel_encoder_current_mode() which is doing something similar to what you're proposing. So probably should just try to reuse that.
Ah yes that should work and will allow me to drop 2 of the 3 preparation patches (I still need the patch which initializes the encoder enough that it can be passed to get_hw_state() from intel_dsi_init_vbt().
So something like this ? :
From 82db375919be9b95e680dc5b1f660d5ef1efcc94 Mon Sep 17 00:00:00 2001 From: Hans de Goede hdegoede@redhat.com Date: Tue, 10 Jul 2018 08:59:27 +0200 Subject: [PATCH] drm/i915/intel_dsi: Read back pclk set by GOP and use that as pclk
On BYT and CHT the GOP sometimes initializes the pclk at a (slightly) different frequency then the pclk which we've calculated.
This commit makes the DSI code read-back the pclk set by the GOP and if that is within a reasonable margin of the calculated pclk, uses that instead.
This fixes the first modeset being a full modeset instead of a fast modeset on systems where the GOP pclk is different.
Changes in v2: -Use intel_encoder_current_mode() to get the pclk setup by the GOP
Signed-off-by: Hans de Goede hdegoede@redhat.com --- drivers/gpu/drm/i915/intel_dsi_vbt.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_dsi_vbt.c b/drivers/gpu/drm/i915/intel_dsi_vbt.c index 4d6ffa7b3e7b..828d5ac0dfef 100644 --- a/drivers/gpu/drm/i915/intel_dsi_vbt.c +++ b/drivers/gpu/drm/i915/intel_dsi_vbt.c @@ -506,6 +506,7 @@ bool intel_dsi_vbt_init(struct intel_dsi *intel_dsi, u16 panel_id) struct mipi_config *mipi_config = dev_priv->vbt.dsi.config; struct mipi_pps_data *pps = dev_priv->vbt.dsi.pps; struct drm_display_mode *mode = dev_priv->vbt.lfp_lvds_vbt_mode; + struct drm_display_mode *curr; u32 bpp; u32 tlpx_ns, extra_byte_count, bitrate, tlpx_ui; u32 ui_num, ui_den; @@ -583,6 +584,23 @@ bool intel_dsi_vbt_init(struct intel_dsi *intel_dsi, u16 panel_id) } else burst_mode_ratio = 100;
+ /* + * On BYT / CRC the GOP sometimes picks a slightly different pclk, + * read back the GOP configured pclk and prefer it over ours. + */ + if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) { + curr = intel_encoder_current_mode(&intel_dsi->base); + if (curr) { + DRM_DEBUG_KMS("Calculated pclk %d GOP %d\n", + pclk, curr->clock); + if (curr->clock >= (pclk * 9 / 10) && + curr->clock <= (pclk * 11 / 10)) + pclk = curr->clock; + + kfree(curr); + } + } + intel_dsi->burst_mode_ratio = burst_mode_ratio; intel_dsi->pclk = pclk;
Note this is untested as I'm travelling at the moment. I will test this when I'm back home and send out a v2.
Regards,
Hans