diff options
Diffstat (limited to 'debian/patches-rt/0320-drm-vmwgfx-Drop-preempt_disable-in-vmw_fifo_ping_hos.patch')
| -rw-r--r-- | debian/patches-rt/0320-drm-vmwgfx-Drop-preempt_disable-in-vmw_fifo_ping_hos.patch | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/debian/patches-rt/0320-drm-vmwgfx-Drop-preempt_disable-in-vmw_fifo_ping_hos.patch b/debian/patches-rt/0320-drm-vmwgfx-Drop-preempt_disable-in-vmw_fifo_ping_hos.patch new file mode 100644 index 000000000..2dc30fc19 --- /dev/null +++ b/debian/patches-rt/0320-drm-vmwgfx-Drop-preempt_disable-in-vmw_fifo_ping_hos.patch @@ -0,0 +1,45 @@ +From fc0f8480da7d2d5927404e67031daba0ca53a1a2 Mon Sep 17 00:00:00 2001 +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Fri, 21 Feb 2020 18:57:11 +0100 +Subject: [PATCH 320/347] drm/vmwgfx: Drop preempt_disable() in + vmw_fifo_ping_host() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +[ Upstream commit b901491e7b9b7a676818d84e482b69be72fc142f ] + +vmw_fifo_ping_host() disables preemption around a test and a register +write via vmw_write(). The write function acquires a spinlock_t typed +lock which is not allowed in a preempt_disable()ed section on +PREEMPT_RT. This has been reported in the bugzilla. + +It has been explained by Thomas Hellstrom that this preempt_disable()ed +section is not required for correctness. + +Remove the preempt_disable() section. + +Link: https://bugzilla.kernel.org/show_bug.cgi?id=206591 +Link: https://lkml.kernel.org/r/0b5e1c65d89951de993deab06d1d197b40fd67aa.camel@vmware.com +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> +--- + drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c | 2 -- + 1 file changed, 2 deletions(-) + +diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c +index d0fd147ef75f..fb5a3461bb8c 100644 +--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c ++++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c +@@ -167,10 +167,8 @@ void vmw_fifo_ping_host(struct vmw_private *dev_priv, uint32_t reason) + { + u32 *fifo_mem = dev_priv->mmio_virt; + +- preempt_disable(); + if (cmpxchg(fifo_mem + SVGA_FIFO_BUSY, 0, 1) == 0) + vmw_write(dev_priv, SVGA_REG_SYNC, reason); +- preempt_enable(); + } + + void vmw_fifo_release(struct vmw_private *dev_priv, struct vmw_fifo_state *fifo) +-- +2.36.1 + |