Re: [Intel-gfx] [PATCH v4 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/20220711-014151
base:   git://anongit.freedesktop.org/drm/drm-tip drm-tip
config: i386-randconfig-a004 (https://download.01.org/0day-ci/archive/20220711/202207110323.aQxXZ1kk-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 6ce63e267aab79ca87bf63453d34dd3909ab978d)
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/fb47ead5e629b3aaaa718d85fb2fb960e77ebe61
        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/20220711-014151
        git checkout fb47ead5e629b3aaaa718d85fb2fb960e77ebe61
        # 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/gt/intel_region_lmem.c:70:44: 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 +70 drivers/gpu/drm/i915/gt/intel_region_lmem.c

    46	
    47	#define LMEM_BAR_NUM 2
    48	static void i915_resize_lmem_bar(struct drm_i915_private *i915, resource_size_t lmem_size)
    49	{
    50		struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
    51		struct pci_bus *root = pdev->bus;
    52		struct resource *root_res;
    53		resource_size_t rebar_size;
    54		u32 pci_cmd;
    55		int i;
    56	
    57		rebar_size = roundup_pow_of_two(pci_resource_len(pdev, LMEM_BAR_NUM));
    58	
    59		if (rebar_size != roundup_pow_of_two(lmem_size))
    60			rebar_size = lmem_size;
    61		else
    62			return;
    63	
    64		/* Find out if root bus contains 64bit memory addressing */
    65		while (root->parent)
    66			root = root->parent;
    67	
    68		pci_bus_for_each_resource(root, root_res, i) {
    69			if (root_res && root_res->flags & (IORESOURCE_MEM |
  > 70						IORESOURCE_MEM_64) && root_res->start > 0x100000000ull)
    71				break;
    72		}
    73	
    74		/* pci_resize_resource will fail anyways */
    75		if (!root_res) {
    76			drm_info(&i915->drm, "Can't resize LMEM BAR - platform support is missing\n");
    77			return;
    78		}
    79	
    80		/* First disable PCI memory decoding references */
    81		pci_read_config_dword(pdev, PCI_COMMAND, &pci_cmd);
    82		pci_write_config_dword(pdev, PCI_COMMAND,
    83				       pci_cmd & ~PCI_COMMAND_MEMORY);
    84	
    85		_resize_bar(i915, LMEM_BAR_NUM, rebar_size);
    86	
    87		pci_assign_unassigned_bus_resources(pdev->bus);
    88		pci_write_config_dword(pdev, PCI_COMMAND, pci_cmd);
    89	}
    90	

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