2.6.31-stable review patch. If anyone has any objections, please let us know. ------------------ From: Zhenyu Wang commit 58a27471d00dc09945cbcfbbc5cbcdcd3c28211d upstream. 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. Signed-off-by: Zhenyu Wang Signed-off-by: Eric Anholt Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/i915_reg.h | 5 +++++ drivers/gpu/drm/i915/intel_display.c | 31 +++++++++++++++++++++++++++---- 2 files changed, 32 insertions(+), 4 deletions(-) --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -1616,6 +1616,11 @@ #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) --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -1764,7 +1764,7 @@ 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) { @@ -1774,7 +1774,8 @@ igdng_compute_m_n(int bytes_per_pixel, i 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); @@ -2396,7 +2397,7 @@ static int intel_crtc_mode_set(struct dr /* 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) { @@ -2415,7 +2416,29 @@ static int intel_crtc_mode_set(struct dr 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); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/