On 12/04/2013 06:30 AM, Paul Berry wrote:
Fast color clears of MSAA buffers work just like fast color clears with non-MSAA buffers, except that the alignment and scaledown requirements are different. --- src/mesa/drivers/dri/i965/brw_blorp_clear.cpp | 131 +++++++++++++++++--------- 1 file changed, 87 insertions(+), 44 deletions(-)diff --git a/src/mesa/drivers/dri/i965/brw_blorp_clear.cpp b/src/mesa/drivers/dri/i965/brw_blorp_clear.cpp index ab472e6..4d03cbe 100644 --- a/src/mesa/drivers/dri/i965/brw_blorp_clear.cpp +++ b/src/mesa/drivers/dri/i965/brw_blorp_clear.cpp @@ -239,8 +239,7 @@ brw_blorp_clear_params::brw_blorp_clear_params(struct brw_context *brw, } /* If we can do this as a fast color clear, do so. */ - if (irb->mt->msaa_layout == INTEL_MSAA_LAYOUT_NONE && - irb->mt->fast_clear_state != INTEL_FAST_CLEAR_STATE_NO_MCS && + if (irb->mt->fast_clear_state != INTEL_FAST_CLEAR_STATE_NO_MCS && !partial_clear && wm_prog_key.use_simd16_replicated_data && is_color_fast_clear_compatible(brw, format, &ctx->Color.ClearColor)) { memset(push_consts, 0xff, 4*sizeof(float)); @@ -251,48 +250,92 @@ brw_blorp_clear_params::brw_blorp_clear_params(struct brw_context *brw, */ unsigned x_align, y_align, x_scaledown, y_scaledown; - /* From the Ivy Bridge PRM, Vol2 Part1 11.7 "MCS Buffer for Render - * Target(s)", beneath the "Fast Color Clear" bullet (p327): - * - * Clear pass must have a clear rectangle that must follow alignment - * rules in terms of pixels and lines as shown in the table - * below. Further, the clear-rectangle height and width must be - * multiple of the following dimensions. If the height and width of - * the render target being cleared do not meet these requirements, - * an MCS buffer can be created such that it follows the requirement - * and covers the RT. - * - * The alignment size in the table that follows is related to the - * alignment size returned by intel_get_non_msrt_mcs_alignment(), but - * with X alignment multiplied by 16 and Y alignment multiplied by 32. - */ - intel_get_non_msrt_mcs_alignment(brw, irb->mt, &x_align, &y_align); - x_align *= 16; - y_align *= 32; - - /* From the Ivy Bridge PRM, Vol2 Part1 11.7 "MCS Buffer for Render - * Target(s)", beneath the "Fast Color Clear" bullet (p327): - * - * In order to optimize the performance MCS buffer (when bound to 1X - * RT) clear similarly to MCS buffer clear for MSRT case, clear rect - * is required to be scaled by the following factors in the - * horizontal and vertical directions: - * - * The X and Y scale down factors in the table that follows are each - * equal to half the alignment value computed above. - */ - x_scaledown = x_align / 2; - y_scaledown = y_align / 2; - - /* From BSpec: 3D-Media-GPGPU Engine > 3D Pipeline > Pixel > Pixel - * Backend > MCS Buffer for Render Target(s) [DevIVB+] > Table "Color - * Clear of Non-MultiSampled Render Target Restrictions": - * - * Clear rectangle must be aligned to two times the number of pixels in - * the table shown below due to 16x16 hashing across the slice. - */ - x_align *= 2; - y_align *= 2; + if (irb->mt->msaa_layout == INTEL_MSAA_LAYOUT_NONE) { + /* From the Ivy Bridge PRM, Vol2 Part1 11.7 "MCS Buffer for Render + * Target(s)", beneath the "Fast Color Clear" bullet (p327): + * + * Clear pass must have a clear rectangle that must follow + * alignment rules in terms of pixels and lines as shown in the + * table below. Further, the clear-rectangle height and width + * must be multiple of the following dimensions. If the height + * and width of the render target being cleared do not meet these + * requirements, an MCS buffer can be created such that it + * follows the requirement and covers the RT. + * + * The alignment size in the table that follows is related to the + * alignment size returned by intel_get_non_msrt_mcs_alignment(), but + * with X alignment multiplied by 16 and Y alignment multiplied by 32. + */ + intel_get_non_msrt_mcs_alignment(brw, irb->mt, &x_align, &y_align); + x_align *= 16; + y_align *= 32; + + /* From the Ivy Bridge PRM, Vol2 Part1 11.7 "MCS Buffer for Render + * Target(s)", beneath the "Fast Color Clear" bullet (p327): + * + * In order to optimize the performance MCS buffer (when bound to + * 1X RT) clear similarly to MCS buffer clear for MSRT case, + * clear rect is required to be scaled by the following factors + * in the horizontal and vertical directions: + * + * The X and Y scale down factors in the table that follows are each + * equal to half the alignment value computed above. + */ + x_scaledown = x_align / 2; + y_scaledown = y_align / 2; + + /* From BSpec: 3D-Media-GPGPU Engine > 3D Pipeline > Pixel > Pixel + * Backend > MCS Buffer for Render Target(s) [DevIVB+] > Table "Color + * Clear of Non-MultiSampled Render Target Restrictions": + * + * Clear rectangle must be aligned to two times the number of + * pixels in the table shown below due to 16x16 hashing across the + * slice. + */ + x_align *= 2; + y_align *= 2; + } else { + /* From the Ivy Bridge PRM, Vol2 Part1 11.7 "MCS Buffer for Render + * Target(s)", beneath the "MSAA Compression" bugget (p326): + * + * Clear pass for this case requires that scaled down primitive + * is sent down with upper left co-ordinate to coincide with + * actual rectangle being cleared. For MSAA, clear rectangle’s + * height and width need to as show in the following table in + * terms of (width,height) of the RT. + * + * MSAA Width of Clear Rect Height of Clear Rect + * 4X Ceil(1/8*width) Ceil(1/2*height) + * 8X Ceil(1/2*width) Ceil(1/2*height) + * + * The text "with upper left co-ordinate to coincide with actual + * rectangle being cleared" is a little confusing--it seems to imply + * that to clear a rectangle from (x,y) to (x+w,y+h), one needs to + * feed the pipeline using the rectangle (x,y) to + * (x+Ceil(w/N),y+Ceil(h/2)), where N is either 2 or 8 depending on + * the number of samples. Experiments indicate that this is not + * quite correct; actually, what the hardware appears to do is to + * align whatever rectangle is sent down the pipeline to the nearest + * multiple of 2x2 blocks, and then scale it up by a factor of N + * horizontally and 2 vertically. So the resulting alignment is 4 + * verticeally and either 4 or 16 horizontally, and the scaledown + * factor is 2 vestically and either 2 or 8 horizontally.
bugget, verticeally, and vestically! oh my! Patches 1-6 are Reviewed-by: Chad Versace <[email protected]> But this patch 7... If the user specifies an ill-aligned clear rectangle, does this code clear a slightly larger, well-aligned rectangle? In other words, will this clear pixels outside the user-specified clear rectangle? Local inspection of the code suggests so to me. But my global understanding of these codepaths is vague. _______________________________________________ mesa-dev mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/mesa-dev
