On 12.04.2016 16:31, Oded Gabbay wrote: > On Tue, Apr 12, 2016 at 10:21 AM, Michel Dänzer <[email protected]> wrote: >> On 11.04.2016 23:34, Oded Gabbay wrote: >>> This patch adds a new field, called "endian_format", to >>> "struct pipe_resource". The new field is of type "enum pipe_endian" and >>> can receive one of two values: >>> - PIPE_ENDIAN_LITTLE >>> - PIPE_ENDIAN_NATIVE >>> >>> PIPE_ENDIAN_NATIVE is initialized to either PIPE_ENDIAN_LITTLE or >>> PIPE_ENDIAN_BIG during build time. >>> >>> This field is needed to provide information to the H/W drivers about the >>> endianess current state or desired state of the resource. In other words, >>> for resources that are the source of the operation, this field indicates >>> the resource's current memory layout endianess (big or little endian). >>> For resources that are the destination of the operation, this field >>> indicates the resource's desired memory layout endianess. >>> >>> This field is mandatory because of how mesa works. When we get into the >>> H/W driver functions, the driver *ususally* doesn't know if it is doing a >>> CPU->GPU, a GPU->CPU, a CPU->CPU or a GPU->GPU operation, as this >>> information is "hidden" by the fact we go through common code >>> paths (state tracker layer). >> >> That shouldn't matter if the formats are defined completely and their >> usage is consistent across the board. Sounds like either or both of >> those conditions aren't completely true yet. I agree with Roland that >> this should be addressed fundamentally rather than adding more hacks on top. > > I disagree with your statement. The formats are defined correctly, > it's just that the software rendering drivers can use the > automatically generated functions in u_format_table.c to handle all > the endianess issues, while H/W drivers won't do it. So H/W drivers > need additional hint.
In other words, the formats aren't used consistently across the board. :) The solution proposed by Marek basically means that there's a conversion between the state tracker and driver interpretations of formats at transfer time. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer _______________________________________________ mesa-dev mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/mesa-dev
