From 2f2a89723681eb86e83ca353fcee64d39b21d225 Mon Sep 17 00:00:00 2001 From: Martin Peres Date: Sat, 30 Jul 2011 23:08:45 +0200 Subject: [PATCH] drm/nv50/ctxprog: enable xfer only when we need it to save power This patch adds instructions to ctxprog and by doing, impact context-switching performance. My testcase showed a 1% performance cost using glxgears that is a context-switch bound application. Please test and report bugs/performance/power/other. --- drivers/gpu/drm/nouveau/nv50_grctx.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nv50_grctx.c b/drivers/gpu/drm/nouveau/nv50_grctx.c index e04fb44..d05c2c3 100644 --- a/drivers/gpu/drm/nouveau/nv50_grctx.c +++ b/drivers/gpu/drm/nouveau/nv50_grctx.c @@ -40,6 +40,9 @@ #define CP_FLAG_UNK0B ((0 * 32) + 0xb) #define CP_FLAG_UNK0B_CLEAR 0 #define CP_FLAG_UNK0B_SET 1 +#define CP_FLAG_XFER_SWITCH ((0 * 32) + 0xe) +#define CP_FLAG_XFER_SWITCH_DISABLE 0 +#define CP_FLAG_XFER_SWITCH_ENABLE 1 #define CP_FLAG_STATE ((0 * 32) + 0x1c) #define CP_FLAG_STATE_STOPPED 0 #define CP_FLAG_STATE_RUNNING 1 @@ -199,6 +202,7 @@ nv50_grctx_init(struct nouveau_grctx *ctx) } cp_set (ctx, STATE, RUNNING); + cp_set (ctx, XFER_SWITCH, ENABLE); /* decide whether we're loading/unloading the context */ cp_bra (ctx, AUTO_SAVE, PENDING, cp_setup_save); cp_bra (ctx, USER_SAVE, PENDING, cp_setup_save); @@ -265,6 +269,7 @@ nv50_grctx_init(struct nouveau_grctx *ctx) cp_name(ctx, cp_exit); cp_set (ctx, USER_SAVE, NOT_PENDING); cp_set (ctx, USER_LOAD, NOT_PENDING); + cp_set (ctx, XFER_SWITCH, DISABLE); cp_set (ctx, STATE, STOPPED); cp_out (ctx, CP_END); ctx->ctxvals_pos += 0x400; /* padding... no idea why you need it */ -- 1.7.6