Wa_16030862157: Update Bandwidth Calculation to account for 16channel memory config.
v2: Logical separation of changes (Suraj, Vinod) WA: 16030862157, 16030875223 Bspec: 69131, 68859 Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Uma Shankar <[email protected]> --- drivers/gpu/drm/i915/display/intel_bw.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_bw.c b/drivers/gpu/drm/i915/display/intel_bw.c index 41539fdfeac5..aaa0350dca78 100644 --- a/drivers/gpu/drm/i915/display/intel_bw.c +++ b/drivers/gpu/drm/i915/display/intel_bw.c @@ -14,6 +14,7 @@ #include "intel_display_regs.h" #include "intel_display_types.h" #include "intel_display_utils.h" +#include "intel_display_wa.h" #include "intel_dram.h" #include "intel_mchbar.h" #include "intel_parent.h" @@ -272,7 +273,14 @@ static int icl_get_qgv_points(struct intel_display *display, case INTEL_DRAM_LPDDR4: case INTEL_DRAM_LPDDR5: qi->t_bl = 16; - qi->max_numchannels = 8; + /* + * Wa_16030862157 + * Xe3p supports a fully-populated 16-channel LPDDR + * config (4 memory controllers x 4 channels); earlier + * D14+ platforms top out at 8. + */ + qi->max_numchannels = + intel_display_wa(display, INTEL_DISPLAY_WA_16030862157) ? 16 : 8; qi->channel_width = 16; qi->deinterleave = 4; break; @@ -624,10 +632,16 @@ static int tgl_get_bw_info(struct intel_display *display, ipqdepth = min(ipqdepthpch, display_bw_params->displayrtids / num_channels); /* + * Wa_16030862157 * clperchgroup = 4kpagespermempage * clperchperblock, - * clperchperblock = 8 / num_channels * interleave + * clperchperblock = max(8 / num_channels, 1) * interleave + * + * The 8 / num_channels truncating divide collapses to 0 for + * >8-channel configs (16-channel: 8 / 16 = 0); the max(..., 1) floor + * keeps clperchperblock >= 1 there while preserving the literal + * truncating divide for <=8-channel configs. */ - clperchgroup = 4 * (8 / num_channels) * qi.deinterleave; + clperchgroup = 4 * max(8 / num_channels, 1) * qi.deinterleave; display->bw.num_qgv_points = qi.num_qgv_points; display->bw.num_psf_gv_points = qi.num_psf_points; -- 2.50.1
