49 lines
2.0 KiB
Diff
49 lines
2.0 KiB
Diff
From 1f738998f8e1a6962ff73d192b2d578631792cdd Mon Sep 17 00:00:00 2001
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Message-Id: <1f738998f8e1a6962ff73d192b2d578631792cdd.1601675153.git.zanussi@kernel.org>
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In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Fri, 21 Feb 2020 18:57:11 +0100
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Subject: [PATCH 320/333] drm/vmwgfx: Drop preempt_disable() in
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vmw_fifo_ping_host()
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz
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[ Upstream commit b901491e7b9b7a676818d84e482b69be72fc142f ]
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vmw_fifo_ping_host() disables preemption around a test and a register
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write via vmw_write(). The write function acquires a spinlock_t typed
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lock which is not allowed in a preempt_disable()ed section on
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PREEMPT_RT. This has been reported in the bugzilla.
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It has been explained by Thomas Hellstrom that this preempt_disable()ed
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section is not required for correctness.
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Remove the preempt_disable() section.
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Link: https://bugzilla.kernel.org/show_bug.cgi?id=206591
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Link: https://lkml.kernel.org/r/0b5e1c65d89951de993deab06d1d197b40fd67aa.camel@vmware.com
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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---
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drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c | 2 --
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1 file changed, 2 deletions(-)
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diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c
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index d0fd147ef75f..fb5a3461bb8c 100644
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--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c
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+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c
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@@ -167,10 +167,8 @@ void vmw_fifo_ping_host(struct vmw_private *dev_priv, uint32_t reason)
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{
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u32 *fifo_mem = dev_priv->mmio_virt;
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- preempt_disable();
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if (cmpxchg(fifo_mem + SVGA_FIFO_BUSY, 0, 1) == 0)
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vmw_write(dev_priv, SVGA_REG_SYNC, reason);
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- preempt_enable();
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}
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void vmw_fifo_release(struct vmw_private *dev_priv, struct vmw_fifo_state *fifo)
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--
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2.17.1
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