On Thu, Feb 23, 2012 at 02:37:06PM +0800, Yuanhan Liu wrote: > On Tue, Feb 21, 2012 at 11:59:17AM -0800, Eric Anholt wrote: > > On Sun, 19 Feb 2012 13:31:33 +0800, Liu Aleaxander <aleaxan...@gmail.com> > > wrote: > > > On Sun, Feb 19, 2012 at 8:54 AM, Eric Anholt <e...@anholt.net> wrote: > > > > On Sat, 18 Feb 2012 23:07:32 +0800, Liu Aleaxander > > > > <aleaxan...@gmail.com> wrote: > > > >> + /* > > > >> + * gl_PointCoord is a FS instead of VS builtin variable, thus is > > > >> not > > > >> + * included in c->nr_setup_regs. But FS need SF do the > > > >> interpolation, > > > >> + * so that here padding the interpolation for gl_PointCoord in > > > >> last. > > > >> + */ > > > >> + if (c->key.do_point_coord) > > > >> + c->nr_setup_regs++; > > > > > > > > So you're writing an extra attribute of setup, but you haven't increased > > > > the size of the URB entry. If the URB full except for pointcoord, you'd > > > > end up writing over the next URB entry and probably hanging the GPU. If > > > > you correctly allocate the URB size and that gets reflected in > > > > urb_read_length, you should be able to read your new attribute. > > > > > > That's maybe the place I don't understand quite well so far. Say, you > > > write attributes into URB from SF thread to FS. I did increase the > > > urb_read_length in wm_state. Is that the allocation you mean? Should > > > I, say, allocate size for extra attributes just for FS in SF stage? If > > > so, would you please tell me how? Since if I understand correctly, the > > > urb_read_length in SF_STATE is counted from the attributes from VF > > > stage. Thus at least urb_read_length in SF stage is not the right > > > place for me to touch, right? > > > > urb_entry_size in the SF is the size of what the SF outputs and is what > > determines how much space is allocated by brw_urb.c > > Thanks for the info. > > Well, I was trying to figure out why this patch doesn't work when the > urb read lenght per each attribute is set to 2 at calculate_urb_setup(), > but it does work when set to 4. I may not quite understand the urb > layout now; and I'm trying to figure it out.
OK, finally, I guess I understand that now. And I wrote another patch to fix this issue. And this time we don't need to write a single PS shader to handle it thus it's much cleaner than this patch. Thanks, Yuanhan Liu _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
