From 09dc1387c9c06cdaf55bc99b35238bd2ec0aed4b Mon Sep 17 00:00:00 2001 From: Thomas Hellstrom Date: Wed, 21 Oct 2015 21:31:49 +0200 Subject: [PATCH] drm/vmwgfx: Stabilize the command buffer submission code This commit addresses some stability problems with the command buffer submission code recently introduced: 1) Make the vmw_cmdbuf_man_process() function handle reruns internally to avoid losing interrupts if the caller forgets to rerun on -EAGAIN. 2) Handle default command buffer allocations using inline command buffers. This avoids rare allocation deadlocks. 3) In case of command buffer errors we might lose fence submissions. Therefore send a new fence after each command buffer error. This will help avoid lengthy fence waits. Signed-off-by: Thomas Hellstrom Reviewed-by: Sinclair Yeh --- drivers/gpu/drm/vmwgfx/vmwgfx_cmdbuf.c | 34 +++++++++++++++----------- 1 file changed, 20 insertions(+), 14 deletions(-) diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_cmdbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_cmdbuf.c index 8a76821177a6..6377e8151000 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_cmdbuf.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_cmdbuf.c @@ -415,16 +415,16 @@ static void vmw_cmdbuf_ctx_process(struct vmw_cmdbuf_man *man, * * Calls vmw_cmdbuf_ctx_process() on all contexts. If any context has * command buffers left that are not submitted to hardware, Make sure - * IRQ handling is turned on. Otherwise, make sure it's turned off. This - * function may return -EAGAIN to indicate it should be rerun due to - * possibly missed IRQs if IRQs has just been turned on. + * IRQ handling is turned on. Otherwise, make sure it's turned off. */ -static int vmw_cmdbuf_man_process(struct vmw_cmdbuf_man *man) +static void vmw_cmdbuf_man_process(struct vmw_cmdbuf_man *man) { - int notempty = 0; + int notempty; struct vmw_cmdbuf_context *ctx; int i; +retry: + notempty = 0; for_each_cmdbuf_ctx(man, i, ctx) vmw_cmdbuf_ctx_process(man, ctx, ¬empty); @@ -440,10 +440,8 @@ static int vmw_cmdbuf_man_process(struct vmw_cmdbuf_man *man) man->irq_on = true; /* Rerun in case we just missed an irq. */ - return -EAGAIN; + goto retry; } - - return 0; } /** @@ -468,8 +466,7 @@ static void vmw_cmdbuf_ctx_add(struct vmw_cmdbuf_man *man, header->cb_context = cb_context; list_add_tail(&header->list, &man->ctx[cb_context].submitted); - if (vmw_cmdbuf_man_process(man) == -EAGAIN) - vmw_cmdbuf_man_process(man); + vmw_cmdbuf_man_process(man); } /** @@ -488,8 +485,7 @@ static void vmw_cmdbuf_man_tasklet(unsigned long data) struct vmw_cmdbuf_man *man = (struct vmw_cmdbuf_man *) data; spin_lock(&man->lock); - if (vmw_cmdbuf_man_process(man) == -EAGAIN) - (void) vmw_cmdbuf_man_process(man); + vmw_cmdbuf_man_process(man); spin_unlock(&man->lock); } @@ -507,6 +503,7 @@ static void vmw_cmdbuf_work_func(struct work_struct *work) struct vmw_cmdbuf_man *man = container_of(work, struct vmw_cmdbuf_man, work); struct vmw_cmdbuf_header *entry, *next; + uint32_t dummy; bool restart = false; spin_lock_bh(&man->lock); @@ -523,6 +520,8 @@ static void vmw_cmdbuf_work_func(struct work_struct *work) if (restart && vmw_cmdbuf_startstop(man, true)) DRM_ERROR("Failed restarting command buffer context 0.\n"); + /* Send a new fence in case one was removed */ + vmw_fifo_send_fence(man->dev_priv, &dummy); } /** @@ -682,7 +681,7 @@ static bool vmw_cmdbuf_try_alloc(struct vmw_cmdbuf_man *man, DRM_MM_SEARCH_DEFAULT, DRM_MM_CREATE_DEFAULT); if (ret) { - (void) vmw_cmdbuf_man_process(man); + vmw_cmdbuf_man_process(man); ret = drm_mm_insert_node_generic(&man->mm, info->node, info->page_size, 0, 0, DRM_MM_SEARCH_DEFAULT, @@ -1168,7 +1167,14 @@ int vmw_cmdbuf_set_pool_size(struct vmw_cmdbuf_man *man, drm_mm_init(&man->mm, 0, size >> PAGE_SHIFT); man->has_pool = true; - man->default_size = default_size; + + /* + * For now, set the default size to VMW_CMDBUF_INLINE_SIZE to + * prevent deadlocks from happening when vmw_cmdbuf_space_pool() + * needs to wait for space and we block on further command + * submissions to be able to free up space. + */ + man->default_size = VMW_CMDBUF_INLINE_SIZE; DRM_INFO("Using command buffers with %s pool.\n", (man->using_mob) ? "MOB" : "DMA"); -- 2.20.1