Module: Mesa Branch: main Commit: 68d56b15d77494a7db237537ccad75849dadf6bf URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=68d56b15d77494a7db237537ccad75849dadf6bf
Author: Nanley Chery <[email protected]> Date: Mon Aug 14 10:41:48 2023 -0400 iris: Zero the clear color before FCV_CCS_E rendering On small-BAR ACM systems, we don't initialize the clear color at resource creation time. This could cause an issue with FCV_CCS_E. Because the rendering and sampling fields may not be in agreement, FCV may generate fast-cleared blocks during rendering and the sampler may interpret them with the wrong values. Thankfully, the register bit which enables FCV on ACM is disabled by default, so there is not an actually issue today. Regardless, this patch implements the fix for this issue now. The next patch will actually skip explicit clear color initialization at resource creation time. So, this fix will be useful for other systems that do have FCV enabled today. Reviewed-by: Sagar Ghuge <[email protected]> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26675> --- src/gallium/drivers/iris/iris_resolve.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-) diff --git a/src/gallium/drivers/iris/iris_resolve.c b/src/gallium/drivers/iris/iris_resolve.c index c68c849c2bf..d245fb55bf1 100644 --- a/src/gallium/drivers/iris/iris_resolve.c +++ b/src/gallium/drivers/iris/iris_resolve.c @@ -1269,14 +1269,32 @@ iris_resource_prepare_render(struct iris_context *ice, uint32_t start_layer, uint32_t layer_count, enum isl_aux_usage aux_usage) { - /* If the resource's clear color is incompatible with render_format, - * replace it with one that is. This process keeps the aux buffer - * compatible with render_format and the resource's format. + /* Replace the resource's clear color with zero if: + * + * - The resource's clear color is incompatible with render_format. This + * avoids corrupting current fast clear blocks and ensures any fast clear + * blocks generated as a result of the render will be recoverable. + * + * - The clear color struct is uninitialized and potentially inconsistent + * with itself. For non-32-bpc formats, the struct consists of different + * fields for rendering and sampling. If rendering can generate + * fast-cleared blocks, we want these to agree so that we can avoid + * partially resolving prior to sampling. Images with modifiers can be + * ignored. Either we will have already initialized their structs to + * zero, or they will have already been consistent at the time of import + * (as defined by drm_fourcc.h) + * + * The only aux usage which requires this process is FCV_CCS_E. Other aux + * usages share a subset of these restrictions and benefit from only some + * of the steps involved with changing the clear color. For now, just keep + * things simple and assume we have the worst case usage of FCV_CCS_E. */ if (!iris_render_formats_color_compatible(render_format, res->surf.format, res->aux.clear_color, - res->aux.clear_color_unknown)) { + res->aux.clear_color_unknown) || + (res->aux.clear_color_unknown && !res->mod_info && + isl_format_get_layout(render_format)->channels.r.bits != 32)) { /* Remove references to the clear color with resolves. */ iris_resource_prepare_access(ice, res, 0, INTEL_REMAINING_LEVELS, 0,
