On Thu, 17 Aug 2017, Jani Nikula <jani.nik...@intel.com> wrote:
> Sometimes it would be most enlightening to debug systems by replacing
> the VBT to be used. For example, in the referenced bug the BIOS provides
> different VBT depending on the boot mode (UEFI vs. legacy). It would be
> interesting to try the failing boot mode with the VBT from the working
> boot, and see if that makes a difference.
>
> Add a module parameter to load the VBT using the firmware loader, not
> unlike the EDID firmware mechanism.
>
> As a starting point for experimenting, one can pick up the BIOS provided
> VBT from /sys/kernel/debug/dri/0/i915_opregion/i915_vbt.
>
> v2: clarify firmware load return value check (Bob)
>
> v3: kfree the loaded firmware blob
>
> References: https://bugs.freedesktop.org/show_bug.cgi?id=97822#c83
> Reviewed-by: Bob Paauwe <bob.j.paa...@intel.com>
> Signed-off-by: Jani Nikula <jani.nik...@intel.com>
And pushed, with Daniel's additional irc ack.
BR,
Jani.
> ---
> drivers/gpu/drm/i915/i915_drv.h | 1 +
> drivers/gpu/drm/i915/i915_params.c | 4 ++++
> drivers/gpu/drm/i915/i915_params.h | 1 +
> drivers/gpu/drm/i915/intel_opregion.c | 45
> +++++++++++++++++++++++++++++++++++
> 4 files changed, 51 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 6c25c8520c87..3ee4fd2a9b41 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -646,6 +646,7 @@ struct intel_opregion {
> u32 swsci_sbcb_sub_functions;
> struct opregion_asle *asle;
> void *rvda;
> + void *vbt_firmware;
> const void *vbt;
> u32 vbt_size;
> u32 *lid_state;
> diff --git a/drivers/gpu/drm/i915/i915_params.c
> b/drivers/gpu/drm/i915/i915_params.c
> index 14e2c2e57f96..8ab003dca113 100644
> --- a/drivers/gpu/drm/i915/i915_params.c
> +++ b/drivers/gpu/drm/i915/i915_params.c
> @@ -118,6 +118,10 @@ MODULE_PARM_DESC(vbt_sdvo_panel_type,
> module_param_named_unsafe(reset, i915.reset, int, 0600);
> MODULE_PARM_DESC(reset, "Attempt GPU resets (0=disabled, 1=full gpu reset,
> 2=engine reset [default])");
>
> +module_param_named_unsafe(vbt_firmware, i915.vbt_firmware, charp, 0400);
> +MODULE_PARM_DESC(vbt_firmware,
> + "Load VBT from specified file under /lib/firmware");
> +
> #if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR)
> module_param_named(error_capture, i915.error_capture, bool, 0600);
> MODULE_PARM_DESC(error_capture,
> diff --git a/drivers/gpu/drm/i915/i915_params.h
> b/drivers/gpu/drm/i915/i915_params.h
> index febbfdbd30bd..ac844709c97e 100644
> --- a/drivers/gpu/drm/i915/i915_params.h
> +++ b/drivers/gpu/drm/i915/i915_params.h
> @@ -28,6 +28,7 @@
> #include <linux/cache.h> /* for __read_mostly */
>
> #define I915_PARAMS_FOR_EACH(func) \
> + func(char *, vbt_firmware); \
> func(int, modeset); \
> func(int, panel_ignore_lid); \
> func(int, semaphores); \
> diff --git a/drivers/gpu/drm/i915/intel_opregion.c
> b/drivers/gpu/drm/i915/intel_opregion.c
> index 2bd03001cc70..98154efcb2f4 100644
> --- a/drivers/gpu/drm/i915/intel_opregion.c
> +++ b/drivers/gpu/drm/i915/intel_opregion.c
> @@ -27,6 +27,7 @@
>
> #include <linux/acpi.h>
> #include <linux/dmi.h>
> +#include <linux/firmware.h>
> #include <acpi/video.h>
>
> #include <drm/drmP.h>
> @@ -829,6 +830,10 @@ void intel_opregion_unregister(struct drm_i915_private
> *dev_priv)
> memunmap(opregion->rvda);
> opregion->rvda = NULL;
> }
> + if (opregion->vbt_firmware) {
> + kfree(opregion->vbt_firmware);
> + opregion->vbt_firmware = NULL;
> + }
> opregion->header = NULL;
> opregion->acpi = NULL;
> opregion->swsci = NULL;
> @@ -912,6 +917,43 @@ static const struct dmi_system_id
> intel_no_opregion_vbt[] = {
> { }
> };
>
> +static int intel_load_vbt_firmware(struct drm_i915_private *dev_priv)
> +{
> + struct intel_opregion *opregion = &dev_priv->opregion;
> + const struct firmware *fw = NULL;
> + const char *name = i915.vbt_firmware;
> + int ret;
> +
> + if (!name || !*name)
> + return -ENOENT;
> +
> + ret = request_firmware(&fw, name, &dev_priv->drm.pdev->dev);
> + if (ret) {
> + DRM_ERROR("Requesting VBT firmware \"%s\" failed (%d)\n",
> + name, ret);
> + return ret;
> + }
> +
> + if (intel_bios_is_valid_vbt(fw->data, fw->size)) {
> + opregion->vbt_firmware = kmemdup(fw->data, fw->size,
> GFP_KERNEL);
> + if (opregion->vbt_firmware) {
> + DRM_DEBUG_KMS("Found valid VBT firmware \"%s\"\n",
> name);
> + opregion->vbt = opregion->vbt_firmware;
> + opregion->vbt_size = fw->size;
> + ret = 0;
> + } else {
> + ret = -ENOMEM;
> + }
> + } else {
> + DRM_DEBUG_KMS("Invalid VBT firmware \"%s\"\n", name);
> + ret = -EINVAL;
> + }
> +
> + release_firmware(fw);
> +
> + return ret;
> +}
> +
> int intel_opregion_setup(struct drm_i915_private *dev_priv)
> {
> struct intel_opregion *opregion = &dev_priv->opregion;
> @@ -974,6 +1016,9 @@ int intel_opregion_setup(struct drm_i915_private
> *dev_priv)
> if (mboxes & MBOX_ASLE_EXT)
> DRM_DEBUG_DRIVER("ASLE extension supported\n");
>
> + if (intel_load_vbt_firmware(dev_priv) == 0)
> + goto out;
> +
> if (dmi_check_system(intel_no_opregion_vbt))
> goto out;
--
Jani Nikula, Intel Open Source Technology Center
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