From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Date: Thu, 15 Dec 2011 21:13:35 +0000 Subject: Re: Should I use FBINFO_VIRTFB? Message-Id: <20111215211335.GA12524@phenom.dumpdata.com> List-Id: References: <4EEA5DA7.3010406@freescale.com> In-Reply-To: <4EEA5DA7.3010406@freescale.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-fbdev@vger.kernel.org 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 > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html