Re: [Intel-gfx] [PATCH i-g-t 1/2] drm/i915: Add support for LMEM PCIe resizable bar

[kernel test robot <lkp@intel.com>]

Hi,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on drm-tip/drm-tip]

url:    https://github.com/intel-lab-lkp/linux/commits/priyanka-dandamudi-intel-com/Add-support-for-LMEM-PCIe-resizable-bar/20220616-201631
base:   git://anongit.freedesktop.org/drm/drm-tip drm-tip
config: i386-randconfig-a013 (https://download.01.org/0day-ci/archive/20220616/202206162313.aYMhL5Br-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project f0e608de27b3d568000046eebf3712ab542979d6)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/0242b37c1e2e73134035a0847c34367331f16cca
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review priyanka-dandamudi-intel-com/Add-support-for-LMEM-PCIe-resizable-bar/20220616-201631
        git checkout 0242b37c1e2e73134035a0847c34367331f16cca
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/gpu/drm/i915/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/i915/i915_driver.c:374:44: warning: result of comparison of constant 4294967296 with expression of type 'resource_size_t' (aka 'unsigned int') is always false [-Wtautological-constant-out-of-range-compare]
                                           IORESOURCE_MEM_64) && root_res->start > 0x100000000ull)
                                                                 ~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
   1 warning generated.


vim +374 drivers/gpu/drm/i915/i915_driver.c

   354	
   355	#define LMEM_BAR_NUM 2
   356	static void i915_resize_lmem_bar(struct drm_i915_private *i915)
   357	{
   358		struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
   359		struct pci_bus *root = pdev->bus;
   360		struct resource *root_res;
   361		resource_size_t rebar_size = __lmem_rebar_size(i915, LMEM_BAR_NUM);
   362		u32 pci_cmd;
   363		int i;
   364	
   365		if (!rebar_size)
   366			return;
   367	
   368		/* Find out if root bus contains 64bit memory addressing */
   369		while (root->parent)
   370			root = root->parent;
   371	
   372		pci_bus_for_each_resource(root, root_res, i) {
   373			if (root_res && root_res->flags & (IORESOURCE_MEM |
 > 374						IORESOURCE_MEM_64) && root_res->start > 0x100000000ull)
   375				break;
   376		}
   377	
   378		/* pci_resize_resource will fail anyways */
   379		if (!root_res) {
   380			drm_info(&i915->drm, "Can't resize LMEM BAR - platform support is missing\n");
   381			return;
   382		}
   383	
   384		/* First disable PCI memory decoding references */
   385		pci_read_config_dword(pdev, PCI_COMMAND, &pci_cmd);
   386		pci_write_config_dword(pdev, PCI_COMMAND,
   387				       pci_cmd & ~PCI_COMMAND_MEMORY);
   388	
   389		__resize_bar(i915, LMEM_BAR_NUM, rebar_size);
   390	
   391		pci_assign_unassigned_bus_resources(pdev->bus);
   392		pci_write_config_dword(pdev, PCI_COMMAND, pci_cmd);
   393	}
   394	

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