<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> <meta name="Generator" content="Microsoft Word 14 (filtered medium)"> <style></style> </head> <body lang="ZH-CN" link="blue" vlink="purple"> <div class="WordSection1"> <o:p> </o:p> <o:p> </o:p> From: magcius@gmail.com [mailto:magcius@gmail.com] On Behalf Of Jasper St. Pierre Sent: Monday, February 10, 2014 10:00 AM To: Wang, Quanxian Cc: wayland-devel@lists.freedesktop.org Subject: Re: Is there any way to let compositor set the data in client space and then return back to client?<o:p></o:p> <o:p> </o:p> <div> What is the "output data"? Is there any reason it needs to be allocated directly in the client's space, rather than streamed across as part of the protocol?<o:p></o:p> [Wang, Quanxian] I want to get the output_list data in compositor, convert them and then return it to client. Client could provide valuable output data for user as a string. Just like, client provide a pool, compositor could input data into the pool.<o:p></o:p> </div> <div> <o:p> </o:p> <div> On Sun, Feb 9, 2014 at 8:58 PM, Wang, Quanxian <<a href="mailto:quanxian.wang@intel.com" target="_blank">quanxian.wang@intel.com</a>> wrote:<o:p></o:p> <div> <div> <o:p></o:p> <o:p></o:p> From: <a href="mailto:magcius@gmail.com" target="_blank">magcius@gmail.com</a> [mailto:<a href="mailto:magcius@gmail.com" target="_blank">magcius@gmail.com</a>] On Behalf Of Jasper St. Pierre Sent: Sunday, February 09, 2014 12:23 AM<o:p></o:p> <div> To: Wang, Quanxian Cc: <a href="mailto:wayland-devel@lists.freedesktop.org" target="_blank">wayland-devel@lists.freedesktop.org</a><o:p></o:p> </div> Subject: Re: Is there any way to let compositor set the data in client space and then return back to client?<o:p></o:p> <o:p></o:p> <div> <div> <div> Well, there's not really anything that allows process A to arbitrarily modify process B's memory. The only thing that's close is memory-mapped files, and that's already what we use to share image data between the client and the compositor.<o:p></o:p> </div> <div> There's also memfd, which is "more secure" than a memory-mapped tmpfile, simply because it allows sealing the fd, so you can be sure it will never change as you try to read from it. But memfd isn't a public API yet.<o:p></o:p> </div> <div> <o:p></o:p> </div> What exactly are you trying to do here?<o:p></o:p> </div> [Wang, Quanxian] I want to create a protocol to get the output data from compositor, I don’t know where to put it for client. So shared memory should be a good way to do that. Anyway, I need to check it how to make it happen. Thanks for your idea.<o:p></o:p> </div> <div> <div> <o:p></o:p> <div> On Sat, Feb 8, 2014 at 3:19 AM, Wang, Quanxian <<a href="mailto:quanxian.wang@intel.com" target="_blank">quanxian.wang@intel.com</a>> wrote:<o:p></o:p> <div> Hi, All<o:p></o:p> <o:p></o:p> I want to allocate some space in client, and let compositor set some data in this space and then return back to client. <o:p></o:p> <o:p></o:p> It seems like user data mechanism.<o:p></o:p> <o:p></o:p> Any way to implement that?<o:p></o:p> <o:p></o:p> Thanks<o:p></o:p> <o:p></o:p> Regards<o:p></o:p> <o:p></o:p> Quanxian Wang<o:p></o:p> <o:p></o:p> </div> _______________________________________________ wayland-devel mailing list <a href="mailto:wayland-devel@lists.freedesktop.org" target="_blank">wayland-devel@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/wayland-devel" target="_blank">http://lists.freedesktop.org/mailman/listinfo/wayland-devel</a><o:p></o:p> </div> -- Jasper<o:p></o:p> </div> </div> </div> </div> </div> -- Jasper<o:p></o:p> </div> </div> </body> </html>