RE: Hardware overlays (8+24?) on Intel i830
On Fri, 25 Jul 2003, Sottek, Matthew J wrote: I understand the need for 8bit displays to support legacy apps; however, RandR (or RENDER? or a combination of the two?) is (or will be) able to support 8bit visuals on a 24bpp display. I am wondering if giving up a guaranteed and constant amount of memory bandwidth on a platform that shares memory bandwidth is not a worse solution than just emulating the 8bit using RandR which only makes the 8bit drawing a greater bandwidth consumer during drawing operations. At 32bpp the chips which support overlays allow you to chose, for each pixel, whether to push 8bits through the palette, or take the 24bit direct; effectively you have two active colormaps (although one of them is fixed to the identity mapping). This means either no colormap flashing between the 8 and 24bit windows, or at worst, moving the focus turns gamma-correction of the 24bit visual on and off. The chips I'm familiar with only have one palette at 24bpp. Emulating GrayScale and PseudoColor 8bit visuals on a 24bpp display requires a compromise. Either they share the same active colormap and flash, or you implement the 8bit palette in software, which means either redrawing the window whenever the colormap changes. So far the consensus has been that a software palette is not acceptable within XFree86, so the extra 8bits pays to get rid of colormap flashing. It is definitely a price that we can't ask everyone to pay, but it seems reasonable to allow users to configure the server in such a way that they don't get cmf between the two dephs. -- Andrew C Aitchison ___ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel
Re: Hardware overlays (8+24?) on Intel i830
It is very useful when dealing with programs of a 5-10 year vintage that were originally developed under X-Windows when 8 bit displays were the best you could get. Since most 8 bit displays used PseudoColor (read Pallete based), they have particular hard-coded logic to deal with the color map. Almost all modern hardware is capable of 24 bit without breaking a sweat (or the memory limit), so modern programs probably just assume TrueColor. So as Linux continues it's into the Enterprise and companies find new life for their old Unix applications that can now run on desktops and laptops running Linux, I would expect that this will become a required feature for Enterprise class drivers. Luckily XFree86 already has support for mixed visuals with a number of drivers. Regards, Matthew Sottek, Matthew J wrote: Yes, The Mobile chipsets could do this under several circumstances. The desktop chips cannot. Could you provide an indication of what such a feature is actually useful for? It seems like more of a toy feature than something with real world applications. Seems like you could actually run at 24bpp and convert from 8 to 24 in the driver with less performance impact than running an additional display plane that consumes width*height*depth*refresh bytes per second guaranteed. -Matt -Original Message- From: Dr Andrew C Aitchison [mailto:[EMAIL PROTECTED] Sent: Thursday, July 24, 2003 5:09 AM To: [EMAIL PROTECTED] Subject: Hardware overlays (8+24?) on Intel i830 I see from http://www.xig.com/Pages/PrReleases/PRMay03-830-O'lays.pdf that hardware overlays (possibly similar to what we currently do in the mga and glint drivers) are possible on the Intel i830 chipset. Does anyone know anything more, or is anyone actually working on adding support to our drivers ? If anyone with a suitable machine is interested in testing for me, and I can get chip-level details, I *might* be interested in writing the code myself. ___ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel
RE: Hardware overlays (8+24?) on Intel i830
mobile devices will always have more limitations, so you wont get rid of any sort of low bpp formats. in multi buffer environments, such as OGL with front, back, depth, stencil, overlay, whatever you will be in need to deal with any sort of pixel depth at the same time as well. for imaging programs there are alpha planes, some are even only 1 bit per pixel, so thats another case where X11 might need to support it for a long time. -Alex. -Original Message- From: Matthew Tippett [mailto:[EMAIL PROTECTED] Sent: Friday, July 25, 2003 17:34 To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: Hardware overlays (8+24?) on Intel i830 It is very useful when dealing with programs of a 5-10 year vintage that were originally developed under X-Windows when 8 bit displays were the best you could get. Since most 8 bit displays used PseudoColor (read Pallete based), they have particular hard-coded logic to deal with the color map. Almost all modern hardware is capable of 24 bit without breaking a sweat (or the memory limit), so modern programs probably just assume TrueColor. So as Linux continues it's into the Enterprise and companies find new life for their old Unix applications that can now run on desktops and laptops running Linux, I would expect that this will become a required feature for Enterprise class drivers. Luckily XFree86 already has support for mixed visuals with a number of drivers. Regards, Matthew Sottek, Matthew J wrote: Yes, The Mobile chipsets could do this under several circumstances. The desktop chips cannot. Could you provide an indication of what such a feature is actually useful for? It seems like more of a toy feature than something with real world applications. Seems like you could actually run at 24bpp and convert from 8 to 24 in the driver with less performance impact than running an additional display plane that consumes width*height*depth*refresh bytes per second guaranteed. -Matt -Original Message- From: Dr Andrew C Aitchison [mailto:[EMAIL PROTECTED] Sent: Thursday, July 24, 2003 5:09 AM To: [EMAIL PROTECTED] Subject: Hardware overlays (8+24?) on Intel i830 I see from http://www.xig.com/Pages/PrReleases/PRMay03-830-O'lays.pdf that hardware overlays (possibly similar to what we currently do in the mga and glint drivers) are possible on the Intel i830 chipset. Does anyone know anything more, or is anyone actually working on adding support to our drivers ? If anyone with a suitable machine is interested in testing for me, and I can get chip-level details, I *might* be interested in writing the code myself. ___ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel ___ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel
RE: Hardware overlays (8+24?) on Intel i830
I understand the need for 8bit displays to support legacy apps; however, RandR (or RENDER? or a combination of the two?) is (or will be) able to support 8bit visuals on a 24bpp display. I am wondering if giving up a guaranteed and constant amount of memory bandwidth on a platform that shares memory bandwidth is not a worse solution than just emulating the 8bit using RandR which only makes the 8bit drawing a greater bandwidth consumer during drawing operations. -Matt -Original Message- From: Alexander Stohr [mailto:[EMAIL PROTECTED] Sent: Friday, July 25, 2003 8:43 AM To: [EMAIL PROTECTED] Cc: Sottek, Matthew J; Matthew Tippett Subject: RE: Hardware overlays (8+24?) on Intel i830 mobile devices will always have more limitations, so you wont get rid of any sort of low bpp formats. in multi buffer environments, such as OGL with front, back, depth, stencil, overlay, whatever you will be in need to deal with any sort of pixel depth at the same time as well. for imaging programs there are alpha planes, some are even only 1 bit per pixel, so thats another case where X11 might need to support it for a long time. -Alex. -Original Message- From: Matthew Tippett [mailto:[EMAIL PROTECTED] Sent: Friday, July 25, 2003 17:34 To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: Hardware overlays (8+24?) on Intel i830 It is very useful when dealing with programs of a 5-10 year vintage that were originally developed under X-Windows when 8 bit displays were the best you could get. Since most 8 bit displays used PseudoColor (read Pallete based), they have particular hard-coded logic to deal with the color map. Almost all modern hardware is capable of 24 bit without breaking a sweat (or the memory limit), so modern programs probably just assume TrueColor. So as Linux continues it's into the Enterprise and companies find new life for their old Unix applications that can now run on desktops and laptops running Linux, I would expect that this will become a required feature for Enterprise class drivers. Luckily XFree86 already has support for mixed visuals with a number of drivers. Regards, Matthew Sottek, Matthew J wrote: Yes, The Mobile chipsets could do this under several circumstances. The desktop chips cannot. Could you provide an indication of what such a feature is actually useful for? It seems like more of a toy feature than something with real world applications. Seems like you could actually run at 24bpp and convert from 8 to 24 in the driver with less performance impact than running an additional display plane that consumes width*height*depth*refresh bytes per second guaranteed. -Matt -Original Message- From: Dr Andrew C Aitchison [mailto:[EMAIL PROTECTED] Sent: Thursday, July 24, 2003 5:09 AM To: [EMAIL PROTECTED] Subject: Hardware overlays (8+24?) on Intel i830 I see from http://www.xig.com/Pages/PrReleases/PRMay03-830-O'lays.pdf that hardware overlays (possibly similar to what we currently do in the mga and glint drivers) are possible on the Intel i830 chipset. Does anyone know anything more, or is anyone actually working on adding support to our drivers ? If anyone with a suitable machine is interested in testing for me, and I can get chip-level details, I *might* be interested in writing the code myself. ___ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel ___ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel
Hardware overlays (8+24?) on Intel i830
I see from http://www.xig.com/Pages/PrReleases/PRMay03-830-O'lays.pdf that hardware overlays (possibly similar to what we currently do in the mga and glint drivers) are possible on the Intel i830 chipset. Does anyone know anything more, or is anyone actually working on adding support to our drivers ? If anyone with a suitable machine is interested in testing for me, and I can get chip-level details, I *might* be interested in writing the code myself. -- Dr. Andrew C. Aitchison Computer Officer, DPMMS, Cambridge [EMAIL PROTECTED] http://www.dpmms.cam.ac.uk/~werdna ___ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel
RE: Hardware overlays (8+24?) on Intel i830
Yes, The Mobile chipsets could do this under several circumstances. The desktop chips cannot. Could you provide an indication of what such a feature is actually useful for? It seems like more of a toy feature than something with real world applications. Seems like you could actually run at 24bpp and convert from 8 to 24 in the driver with less performance impact than running an additional display plane that consumes width*height*depth*refresh bytes per second guaranteed. -Matt -Original Message- From: Dr Andrew C Aitchison [mailto:[EMAIL PROTECTED] Sent: Thursday, July 24, 2003 5:09 AM To: [EMAIL PROTECTED] Subject: Hardware overlays (8+24?) on Intel i830 I see from http://www.xig.com/Pages/PrReleases/PRMay03-830-O'lays.pdf that hardware overlays (possibly similar to what we currently do in the mga and glint drivers) are possible on the Intel i830 chipset. Does anyone know anything more, or is anyone actually working on adding support to our drivers ? If anyone with a suitable machine is interested in testing for me, and I can get chip-level details, I *might* be interested in writing the code myself. -- Dr. Andrew C. Aitchison Computer Officer, DPMMS, Cambridge [EMAIL PROTECTED] http://www.dpmms.cam.ac.uk/~werdna ___ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel ___ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel
