From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartlomiej Zolnierkiewicz Date: Mon, 25 Jun 2018 16:49:44 +0000 Subject: Re: [PATCH v2 2/2] fbdev/efifb: honour UEFI memory map attributes when mapping the fb Message-Id: <1836458.I28Yoh407K@amdc3058> List-Id: References: <20180622075250.14075-3-ard.biesheuvel@linaro.org> In-Reply-To: <20180622075250.14075-3-ard.biesheuvel@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-fbdev@vger.kernel.org On Monday, June 25, 2018 11:58:11 AM Ard Biesheuvel wrote: > ,On 22 June 2018 at 09:52, Ard Biesheuvel wrote: > > If the framebuffer address provided by the Graphics Output Protocol > > (GOP) is covered by the UEFI memory map, it will tell us which memory > > attributes are permitted when mapping this region. In some cases, > > (KVM guest on ARM), violating this will result in loss of coherency, > > which means that updates sent to the framebuffer by the guest will > > not be observeable by the host, and the emulated display simply does > > not work. > > > > So if the memory map contains such a description, take the attributes > > field into account, and add support for creating WT or WB mappings of > > the framebuffer region. > > > > Cc: linux-fbdev@vger.kernel.org > > Cc: Bartlomiej Zolnierkiewicz > > Cc: Peter Jones > > Tested-by: Laszlo Ersek > > Signed-off-by: Ard Biesheuvel > > Bartlomiej, do you have any comments on this patch? If not, I would > like to queue it in the efi tree. > > @@ -164,6 +168,8 @@ static int efifb_probe(struct platform_device *dev) > > unsigned int size_remap; > > unsigned int size_total; > > char *option = NULL; > > + efi_memory_desc_t md; > > + > > minor nit: redundant newline the rest looks fine to me Acked-by: Bartlomiej Zolnierkiewicz Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics