From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: linux-fbdev@vger.kernel.org
Subject: Re: Should I use FBINFO_VIRTFB?
Date: Thu, 15 Dec 2011 21:13:35 +0000 [thread overview]
Message-ID: <20111215211335.GA12524@phenom.dumpdata.com> (raw)
In-Reply-To: <4EEA5DA7.3010406@freescale.com>
On Thu, Dec 15, 2011 at 02:50:47PM -0600, Timur Tabi wrote:
> I'm cleaning up my fbdev driver, and I just noticed FBINFO_VIRTFB:
>
> #define FBINFO_VIRTFB 0x0004 /* FB is System RAM, not device. */
>
> I am currently not setting this flag, but I am allocating my framebuffer in system ram via dma_alloc_coherent(). I don't see any good documentation for this flag, but I suspect I should be enabling it. What exactly does this flag do?
It basically inhibits from using VM_IO which should not be set on
System RAM. In your case you are using System RAM, so please do set it.
>
> I'd also like some explanation for these two macros, which appear to be related:
>
> #define FBINFO_PARTIAL_PAN_OK 0x0040 /* otw use pan only for double-buffering */
> #define FBINFO_READS_FAST 0x0080 /* soft-copy faster than rendering */
Not really. They have a different function, but you are better of looking in the code
to see how they are used.
>
> --
> Timur Tabi
> Linux kernel developer at Freescale
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in
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next prev parent reply other threads:[~2011-12-15 21:13 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-15 20:50 Should I use FBINFO_VIRTFB? Timur Tabi
2011-12-15 21:13 ` Konrad Rzeszutek Wilk [this message]
2011-12-15 22:10 ` Timur Tabi
2011-12-16 11:53 ` Geert Uytterhoeven
2011-12-16 18:18 ` Timur Tabi
2011-12-16 20:16 ` Geert Uytterhoeven
2011-12-19 16:08 ` Timur Tabi
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