On 1/19/22 16:50, Thomas Zimmermann wrote: [snip] >>>> IMHO the best solution is to drop IORESOURCE_BUSY from sysfb and have >>>> drivers register/release the range with _BUSY. That would signal the >>>> memory belongs to the sysfb device but is not busy unless a driver >>>> has >>>> been bound. After simplefb released the range, it should be 'non- >>>> busy' >>>> again and available for vmwgfx. Simpledrm does a hot-unplug of the >>>> sysfb >>>> device, so the memory range gets released entirely. If you want, I'll >>>> prepare some patches for this scenario. >>> >>> Attached is a patch that implements this. Doing >>> >>> cat /proc/iomem >>> ... >>> e0000000-efffffff : 0000:00:02.0 >>> >>> e0000000-e07e8fff : BOOTFB >>> >>> e0000000-e07e8fff : simplefb >>> >>> ... >>> >>> shows the memory. 'BOOTFB' is the simple-framebuffer device and >>> 'simplefb' is the driver. Only the latter uses _BUSY. Same for >>> and the memory canbe acquired by vmwgfx. >>> >>> Zack, please test this patch. If it works, I'll send out the real >>> patchset. >> >> Hmm, the patch looks good but it doesn't work. After boot: /proc/iomem >> 50000000-7fffffff : pcie@0x40000000 >> 78000000-7fffffff : 0000:00:0f.0 >> 78000000-782fffff : BOOTFB >> >> and vmwgfx fails on pci_request_regions: >> >> kernel: fb0: switching to vmwgfx from simple >> kernel: Console: switching to colour dummy device 80x25 >> kernel: vmwgfx 0000:00:0f.0: BAR 2: can't reserve [mem 0x78000000- >> 0x7fffffff 64bit pref] >> kernel: vmwgfx: probe of 0000:00:0f.0 failed with error -16 >> >> leaving the system without a fb driver. > > OK, I suspect that it would work if you use simpledrm instead of > simplefb. Could you try please? You'd have to build DRM and simpledrm > into the kernel binary. > Yes, I believe that should work. Zack, could you please try if just the following [0] make it works ? That is, dropping the IORESOURCE_BUSY but not doing the memory region request / release in simplefb and keeping it in the vmwgfx driver. [0]: >From da6de1430b9dc252eccf2d6fee0446d33375fa6d Mon Sep 17 00:00:00 2001 From: Javier Martinez Canillas <javierm@xxxxxxxxxx> Date: Wed, 19 Jan 2022 14:41:25 +0100 Subject: [PATCH] drivers/firmware: Don't mark as busy the simple-framebuffer IO resource The sysfb_create_simplefb() function requests a IO memory resource for the simple-framebuffer platform device, but it also marks it as busy which led to drivers requesting the same memory resource to fail. Let's drop the IORESOURCE_BUSY flag and let drivers to request it as busy instead. Signed-off-by: Javier Martinez Canillas <javierm@xxxxxxxxxx> --- drivers/firmware/sysfb_simplefb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/firmware/sysfb_simplefb.c b/drivers/firmware/sysfb_simplefb.c index 303a491e520d..76c4abc42a30 100644 --- a/drivers/firmware/sysfb_simplefb.c +++ b/drivers/firmware/sysfb_simplefb.c @@ -99,7 +99,7 @@ __init int sysfb_create_simplefb(const struct screen_info *si, /* setup IORESOURCE_MEM as framebuffer memory */ memset(&res, 0, sizeof(res)); - res.flags = IORESOURCE_MEM | IORESOURCE_BUSY; + res.flags = IORESOURCE_MEM; res.name = simplefb_resname; res.start = base; res.end = res.start + length - 1; -- 2.33.1
