The following commit has been merged in the linux branch: commit 58a27471d00dc09945cbcfbbc5cbcdcd3c28211d Author: Zhenyu Wang zhenyuw@linux.intel.com Date: Fri Sep 25 08:01:28 2009 +0000
drm/i915: Fix FDI M/N setting according with correct color depth
FDI M/N calculation hasn't taken the current pipe color depth into account, but always set as 24bpp. This one checks current pipe color depth setting, and change FDI M/N calculation a little to use bits_per_pixel first, then convert to bytes_per_pixel later.
This fixes display corrupt issue on Arrandle LVDS with 1600x900 panel in 18bpp dual-channel mode.
Cc: Stable Team stable@kernel.org Signed-off-by: Zhenyu Wang zhenyuw@linux.intel.com Signed-off-by: Eric Anholt eric@anholt.net
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 5f92724..0dd87a7 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -1782,6 +1782,11 @@ #define PIPE_START_VBLANK_INTERRUPT_STATUS (1UL<<2) /* 965 or later */ #define PIPE_VBLANK_INTERRUPT_STATUS (1UL<<1) #define PIPE_OVERLAY_UPDATED_STATUS (1UL<<0) +#define PIPE_BPC_MASK (7 << 5) /* Ironlake */ +#define PIPE_8BPC (0 << 5) +#define PIPE_10BPC (1 << 5) +#define PIPE_6BPC (2 << 5) +#define PIPE_12BPC (3 << 5)
#define DSPARB 0x70030 #define DSPARB_CSTART_MASK (0x7f << 7) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index be7fada..8278d9d 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -2082,7 +2082,7 @@ fdi_reduce_ratio(u32 *num, u32 *den) #define LINK_N 0x80000
static void -igdng_compute_m_n(int bytes_per_pixel, int nlanes, +igdng_compute_m_n(int bits_per_pixel, int nlanes, int pixel_clock, int link_clock, struct fdi_m_n *m_n) { @@ -2092,7 +2092,8 @@ igdng_compute_m_n(int bytes_per_pixel, int nlanes,
temp = (u64) DATA_N * pixel_clock; temp = div_u64(temp, link_clock); - m_n->gmch_m = div_u64(temp * bytes_per_pixel, nlanes); + m_n->gmch_m = div_u64(temp * bits_per_pixel, nlanes); + m_n->gmch_m >>= 3; /* convert to bytes_per_pixel */ m_n->gmch_n = DATA_N; fdi_reduce_ratio(&m_n->gmch_m, &m_n->gmch_n);
@@ -2766,7 +2767,7 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
/* FDI link */ if (IS_IGDNG(dev)) { - int lane, link_bw; + int lane, link_bw, bpp; /* eDP doesn't require FDI link, so just set DP M/N according to current link config */ if (is_edp) { @@ -2785,7 +2786,29 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc, lane = 4; link_bw = 270000; } - igdng_compute_m_n(3, lane, target_clock, + + /* determine panel color depth */ + temp = I915_READ(pipeconf_reg); + + switch (temp & PIPE_BPC_MASK) { + case PIPE_8BPC: + bpp = 24; + break; + case PIPE_10BPC: + bpp = 30; + break; + case PIPE_6BPC: + bpp = 18; + break; + case PIPE_12BPC: + bpp = 36; + break; + default: + DRM_ERROR("unknown pipe bpc value\n"); + bpp = 24; + } + + igdng_compute_m_n(bpp, lane, target_clock, link_bw, &m_n); }