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From: Thomas Hellstrom <thellstrom@vmware.com>
To: Linux-graphics-maintainer <Linux-graphics-maintainer@vmware.com>,
	"bigeasy@linutronix.de" <bigeasy@linutronix.de>
Cc: "tglx@linutronix.de" <tglx@linutronix.de>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>
Subject: Re: [PATCH 1/2] drm/vmwgfx: Drop preempt_disable() in vmw_fifo_ping_host()
Date: Wed, 26 Feb 2020 15:01:15 +0000	[thread overview]
Message-ID: <b2580fd686c9fea6afdb25f94adeab544a5c1d66.camel@vmware.com> (raw)
In-Reply-To: <20200224140726.1550689-1-bigeasy@linutronix.de>

On Mon, 2020-02-24 at 15:07 +0100, Sebastian Andrzej Siewior wrote:
> 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.
> 

Hi, Sebastian,

I suppose there isn't something like a preempt_disable_unless_RT()
macro?

If not,
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>

I'll include in the next vmwgfx-next pull request

Thanks,
Thomas

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  parent reply	other threads:[~2020-02-26 15:01 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-24 14:07 [PATCH 1/2] drm/vmwgfx: Drop preempt_disable() in vmw_fifo_ping_host() Sebastian Andrzej Siewior
2020-02-24 14:07 ` [PATCH 2/2] drm/vmwgfx: Remove a few unused functions Sebastian Andrzej Siewior
2020-02-28 11:42   ` Emil Velikov
2020-03-02  9:35     ` [PATCH 2/2 v2] " Sebastian Andrzej Siewior
2020-02-26 15:01 ` Thomas Hellstrom [this message]
2020-02-27 15:54   ` [PATCH 1/2] drm/vmwgfx: Drop preempt_disable() in vmw_fifo_ping_host() bigeasy

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