On Wed, 20 Dec 2023, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote:
> On Tue, Dec 19, 2023 at 05:49:52PM -0800, Radhakrishna Sripada wrote:
>> Discrete cards do not have ACPI opregion. The vbt is stored in a special
>> flash accessible by the display controller. In order to access the vbt
>> in such cases, re-use the vbt, vbt_size fields in the opregion structure.
>
> Why?
The i915_vbt debugfs file probably does not work for VBT from SPI
flash. We should fix that.
But this patch is not the way to go. If the VBT does not come from
opregion, it shouldn't be stored in the opregion structures. Maybe this
needs another abstraction layer. *grin*.
Specifically, one of the problems here is that the allocation and free
of the VBT originating from SPI flash happens at completely different
modules and abstraction layers. That's usually a recipe for disaster
later.
BR,
Jani.
>
>>
>> We should move away from storing the vbt in the opregion and store it,
>> if required in the vbt structure.
>>
>> Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@xxxxxxxxx>
>> ---
>> drivers/gpu/drm/i915/display/intel_bios.c | 44 ++++++++++---------
>> drivers/gpu/drm/i915/display/intel_opregion.c | 7 ++-
>> 2 files changed, 29 insertions(+), 22 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
>> index 736499a6e2c7..cbfbc56ff5b2 100644
>> --- a/drivers/gpu/drm/i915/display/intel_bios.c
>> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
>> @@ -2930,12 +2930,11 @@ static u32 intel_spi_read(struct intel_uncore *uncore, u32 offset)
>> return intel_uncore_read(uncore, PRIMARY_SPI_TRIGGER);
>> }
>>
>> -static struct vbt_header *spi_oprom_get_vbt(struct drm_i915_private *i915)
>> +static struct vbt_header *spi_oprom_get_vbt(struct drm_i915_private *i915, u16 *vbt_size)
>> {
>> u32 count, data, found, store = 0;
>> u32 static_region, oprom_offset;
>> u32 oprom_size = 0x200000;
>> - u16 vbt_size;
>> u32 *vbt;
>>
>> static_region = intel_uncore_read(&i915->uncore, SPI_STATIC_REGIONS);
>> @@ -2957,18 +2956,18 @@ static struct vbt_header *spi_oprom_get_vbt(struct drm_i915_private *i915)
>> goto err_not_found;
>>
>> /* Get VBT size and allocate space for the VBT */
>> - vbt_size = intel_spi_read(&i915->uncore,
>> + *vbt_size = intel_spi_read(&i915->uncore,
>> found + offsetof(struct vbt_header, vbt_size));
>> - vbt_size &= 0xffff;
>> + *vbt_size &= 0xffff;
>>
>> - vbt = kzalloc(round_up(vbt_size, 4), GFP_KERNEL);
>> + vbt = kzalloc(round_up(*vbt_size, 4), GFP_KERNEL);
>> if (!vbt)
>> goto err_not_found;
>>
>> - for (count = 0; count < vbt_size; count += 4)
>> + for (count = 0; count < *vbt_size; count += 4)
>> *(vbt + store++) = intel_spi_read(&i915->uncore, found + count);
>>
>> - if (!intel_bios_is_valid_vbt(vbt, vbt_size))
>> + if (!intel_bios_is_valid_vbt(vbt, *vbt_size))
>> goto err_free_vbt;
>>
>> drm_dbg_kms(&i915->drm, "Found valid VBT in SPI flash\n");
>> @@ -2977,16 +2976,16 @@ static struct vbt_header *spi_oprom_get_vbt(struct drm_i915_private *i915)
>>
>> err_free_vbt:
>> kfree(vbt);
>> + *vbt_size = 0;
>> err_not_found:
>> return NULL;
>> }
>>
>> -static struct vbt_header *oprom_get_vbt(struct drm_i915_private *i915)
>> +static struct vbt_header *oprom_get_vbt(struct drm_i915_private *i915, u16 *vbt_size)
>> {
>> struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
>> void __iomem *p = NULL, *oprom;
>> struct vbt_header *vbt;
>> - u16 vbt_size;
>> size_t i, size;
>>
>> oprom = pci_map_rom(pdev, &size);
>> @@ -3011,21 +3010,21 @@ static struct vbt_header *oprom_get_vbt(struct drm_i915_private *i915)
>> goto err_unmap_oprom;
>> }
>>
>> - vbt_size = ioread16(p + offsetof(struct vbt_header, vbt_size));
>> - if (vbt_size > size) {
>> + *vbt_size = ioread16(p + offsetof(struct vbt_header, vbt_size));
>> + if (*vbt_size > size) {
>> drm_dbg(&i915->drm,
>> - "VBT incomplete (vbt_size overflows)\n");
>> + "VBT incomplete (*vbt_size overflows)\n");
>> goto err_unmap_oprom;
>> }
>>
>> /* The rest will be validated by intel_bios_is_valid_vbt() */
>> - vbt = kmalloc(vbt_size, GFP_KERNEL);
>> + vbt = kmalloc(*vbt_size, GFP_KERNEL);
>> if (!vbt)
>> goto err_unmap_oprom;
>>
>> - memcpy_fromio(vbt, p, vbt_size);
>> + memcpy_fromio(vbt, p, *vbt_size);
>>
>> - if (!intel_bios_is_valid_vbt(vbt, vbt_size))
>> + if (!intel_bios_is_valid_vbt(vbt, *vbt_size))
>> goto err_free_vbt;
>>
>> pci_unmap_rom(pdev, oprom);
>> @@ -3036,6 +3035,7 @@ static struct vbt_header *oprom_get_vbt(struct drm_i915_private *i915)
>>
>> err_free_vbt:
>> kfree(vbt);
>> + *vbt_size = 0;
>> err_unmap_oprom:
>> pci_unmap_rom(pdev, oprom);
>>
>> @@ -3052,8 +3052,10 @@ static struct vbt_header *oprom_get_vbt(struct drm_i915_private *i915)
>> */
>> void intel_bios_init(struct drm_i915_private *i915)
>> {
>> + struct intel_opregion *opregion = &i915->display.opregion;
>> const struct vbt_header *vbt = i915->display.opregion.vbt;
>> struct vbt_header *oprom_vbt = NULL;
>> + u16 vbt_size;
>> const struct bdb_header *bdb;
>>
>> INIT_LIST_HEAD(&i915->display.vbt.display_devices);
>> @@ -3072,13 +3074,15 @@ void intel_bios_init(struct drm_i915_private *i915)
>> * PCI mapping
>> */
>> if (!vbt && IS_DGFX(i915)) {
>> - oprom_vbt = spi_oprom_get_vbt(i915);
>> - vbt = oprom_vbt;
>> + oprom_vbt = spi_oprom_get_vbt(i915, &vbt_size);
>> + opregion->vbt = vbt = oprom_vbt;
>> + opregion->vbt_size = (u32)vbt_size;
>> }
>>
>> if (!vbt) {
>> - oprom_vbt = oprom_get_vbt(i915);
>> - vbt = oprom_vbt;
>> + oprom_vbt = oprom_get_vbt(i915, &vbt_size);
>> + opregion->vbt = vbt = oprom_vbt;
>> + opregion->vbt_size = (u32)vbt_size;
>> }
>>
>> if (!vbt)
>> @@ -3111,8 +3115,6 @@ void intel_bios_init(struct drm_i915_private *i915)
>> /* Further processing on pre-parsed or generated child device data */
>> parse_sdvo_device_mapping(i915);
>> parse_ddi_ports(i915);
>> -
>> - kfree(oprom_vbt);
>> }
>>
>> static void intel_bios_init_panel(struct drm_i915_private *i915,
>> diff --git a/drivers/gpu/drm/i915/display/intel_opregion.c b/drivers/gpu/drm/i915/display/intel_opregion.c
>> index 1ce785db6a5e..20b2160e9d0e 100644
>> --- a/drivers/gpu/drm/i915/display/intel_opregion.c
>> +++ b/drivers/gpu/drm/i915/display/intel_opregion.c
>> @@ -1244,8 +1244,13 @@ void intel_opregion_cleanup(struct drm_i915_private *i915)
>> {
>> struct intel_opregion *opregion = &i915->display.opregion;
>>
>> - if (!opregion->header)
>> + if (!opregion->header) {
>> + if (opregion->vbt) {
>> + kfree(opregion->vbt);
>> + opregion->vbt_size = 0;
>> + }
>> return;
>> + }
>>
>> /* just clear all opregion memory pointers now */
>> memunmap(opregion->header);
>> --
>> 2.34.1
--
Jani Nikula, Intel
