Hi, Erdi.
> This patch adds two new ioctl's to the VIA Unichrome/Pro DRM driver: > DRM_IOCTL_VIA_DMA_INIT > DRM_IOCTL_VIA_CMDBUFFER > > The first call sets up an area in AGP memory that will be used as the > ring buffer. The second call copies a command buffer from user space > memory to the ring buffer. > > The motivation for this patch is to avoid the wait for engine idle call > before each buffer flush in the current DRI driver. With this patch, > the DRI driver can continue to flush its buffer as long as there is free > space in the ring buffer. > > This patch adds an additional copy operation on the command buffer. > This buffer copying is necessary to support multiple DRI clients > rendering simultaneously. Otherwise, more CPU time will be spent in the > busy loop waiting for engine idle between DRI context switch. Even in > the single client case, the tradeoff is reasonable in comparision to the > kernel call to check for free buffer space for the client to render > directly to the ring buffer. > > Once the DRI driver code is changed to utilize the ring buffer, we don't > need to allow user space access to MMIO registers by non-privileged user > applications. Hopefully that will make the Unichrome DRI driver secure > enough to leave Mesa CVS. > I just noticed that you are using a 2d BITBLT to temporarily stall the command regulator for a moment. I believe the XAA implementation in all current via 2d X server drivers out there assume that they are reasonably alone in using the 2d engine and that they expext that some registers are not changed by other applications. This will probably at least break the accelerated X server pixmap cache, unless used 2d engine registers are restored after the BITBLT. I plan to clean up the unichrome 2D driver with respect to this, but I'm not sure when this will happen. W respect to our previous discussion regarding the Mpeg2 decoder I'll try programming it using the 2D commands. It might work. Thanks for the info. Is there any chance of having a command stream completion interrupt implementation? /Thomas ------------------------------------------------------- SF.Net email is sponsored by Shop4tech.com-Lowest price on Blank Media 100pk Sonic DVD-R 4x for only $29 -100pk Sonic DVD+R for only $33 Save 50% off Retail on Ink & Toner - Free Shipping and Free Gift. http://www.shop4tech.com/z/Inkjet_Cartridges/9_108_r285 -- _______________________________________________ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
