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.ca...@vmware.com Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de> --- 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 e5252ef3812f0..6941689085ed3 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c @@ -169,10 +169,8 @@ 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) -- 2.25.1 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
