Responses inline > -----Original Message----- > From: Ard Biesheuvel [mailto:[email protected]] > Sent: 25 October 2017 19:10 > To: Evan Lloyd <[email protected]> > Cc: [email protected]; "[email protected]"@arm.com; > "[email protected]"@arm.com; > "[email protected]"@arm.com; "[email protected]"@arm.com > Subject: Re: [PATCH 18/19] ArmPlatformPkg: Reserving framebuffer at > build > > On 26 September 2017 at 21:15, <[email protected]> wrote: > > From: Girish Pathak <[email protected]> > > > > Currently frame buffer memory is either reserved in special VRAM or > > dynamically allocated using boot services memory allocation functions. > > When allocated using boot services calls the memory has to be > > allocated as EfiBootServicesData. Unfortunately failures have been > > seen with this case. There is also an unfortunate lack of control on > > the placement of the frmae buffer. > > > > This change introduces two PCDs, PcdArmLcdFrameBufferBase and > > PcdArmLcdFrameBufferSize which enable build time reservation of the > > frame buffer, avoiding the need to allocate dynamically. This allows > > the frame buffer to appear as "I/O memory" outside of the normal RAM > > map, which is similar to the "VRAM" case. > > > > This change has no impact on current code, only enables the option of > > build time reservation of frame buffers. > > > > Where is the memory actually being reserved? And if it is reserved, how can > the OS reclaim it if it is not interested in using the GOP?
[[Evan Lloyd]] The memory is reserved by whatever sets the Pcd - normally the .dsc. It may or may not be system RAM. If it is excised from system memory, then there is no way for the OS to reclaim it, as it can't differentiate that from the VRAM case. I'm not sure I see the relevance of that anyway. Is our objective to provide restricted firmware tightly tuned for a specific operating system in an unrealistic mode, or to provide a generic example of firmware exercising the standard interfaces and testing real use cases? Regards, Evan > > > > Contributed-under: TianoCore Contribution Agreement 1.1 > > Signed-off-by: Girish Pathak <[email protected]> > > Signed-off-by: Evan Lloyd <[email protected]> > > --- > > ArmPlatformPkg/ArmPlatformPkg.dec > > | 4 ++++ > > ... > > -- > > Guid("CE165669-3EF3-493F-B85D-6190EE5B9759") > > IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
