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drm/i915/glk: Apply cdclk workaround for DP audio 

Implement the DP-Audio cdclk restriction for GLK, similar to what is
implemented for BDW and other GEN9 platforms. The max. pixel clock
adjustment for GLK, however factors in the 2 pixels per clock output that
GLK generates.

Separating min. cdclk and max. pixel_rate would be nicer, but let's
defer that to future and fix the GLK bug for now.

Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1488931972-2865-1-git-send-email-dhinakaran.pandiyan@intel.com
This commit is contained in:
Pandiyan, Dhinakaran 2017-03-07 16:12:51 -08:00 committed by Paulo Zanoni
parent 9f7886d07f
commit 78cfa580f8
1 changed files with 11 additions and 6 deletions
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17
drivers/gpu/drm/i915/intel_cdclk.c
View File

@ -1442,16 +1442,21 @@ static int bdw_adjust_min_pipe_pixel_rate(struct intel_crtc_state *crtc_state,
if (IS_BROADWELL(dev_priv) && crtc_state->ips_enabled)
pixel_rate = DIV_ROUND_UP(pixel_rate * 100, 95);
/* BSpec says "Do not use DisplayPort with CDCLK less than
* 432 MHz, audio enabled, port width x4, and link rate
* HBR2 (5.4 GHz), or else there may be audio corruption or
* screen corruption."
/* BSpec says "Do not use DisplayPort with CDCLK less than 432 MHz,
* audio enabled, port width x4, and link rate HBR2 (5.4 GHz), or else
* there may be audio corruption or screen corruption." This cdclk
* restriction for GLK is 316.8 MHz and since GLK can output two
* pixels per clock, the pixel rate becomes 2 * 316.8 MHz.
*/
if (intel_crtc_has_dp_encoder(crtc_state) &&
crtc_state->has_audio &&
crtc_state->port_clock >= 540000 &&
crtc_state->lane_count == 4)
pixel_rate = max(432000, pixel_rate);
crtc_state->lane_count == 4) {
if (IS_GEMINILAKE(dev_priv))
pixel_rate = max(2 * 316800, pixel_rate);
else
pixel_rate = max(432000, pixel_rate);
}
return pixel_rate;
}