RE: [PATCH] video: hyperv_fb: Allow resolutions with size > 64 MB for Gen1

From: Haiyang Zhang haiyangz@microsoft.com

...

...

...

• if (gen2vm) {

• pot_start = 0;
  

• pot_end = -1;
  

• } else {

• if (!(pci_resource_flags(pdev, 0) & IORESOURCE_MEM) ||
  

•     pci_resource_len(pdev, 0) < screen_fb_size) {
  

• 	pr_err("Resource not available or (0x%lx < 0x%lx)\n",
  

• 	       (unsigned long) pci_resource_len(pdev, 0),
  

• 	       (unsigned long) screen_fb_size);
  

• 	goto err1;
  

This restriction has been in place since day 1. Haiyang, you wrote this driver. Can you comment on whether this change here is sensible?

When I initially implemented this driver 10 years ago, I believe there was smaller limit for the fb... But I think this patch is good for the newer MMIO alloc scheme. I hope to see reviews also from @Dexuan Cui @Michael Kelley (LINUX) who are more familiar with the PCI/BAR/MMIO area.

Thanks,

• Haiyang

The patch looks good to me but I suggest we check with the Hyper-V team to figure out how a Gen1 Windows VM supports a higher resolution that needs a VRAM size of more than 64MB. Just in case we miss something..

Thanks, -- Dexuan