[Intel-gfx] [REGRESSION] drm/i915/gen9: Removed byte swapping for csr firmware

Daniel Vetter daniel at ffwll.ch
Mon Sep 14 00:35:15 PDT 2015 

On Fri, Sep 11, 2015 at 06:29:19PM +0300, Mika Kuoppala wrote:
> Daniel Vetter <daniel at ffwll.ch> writes:
> 
> > On Tue, Aug 04, 2015 at 11:25:40AM +0530, Animesh Manna wrote:
> >> 
> >> 
> >> On 8/4/2015 9:16 AM, Nagaraju, Vathsala wrote:
> >> >"This patch contains the changes to remove the byte swapping logic introduced with old dmc firmware."
> >> >Which version of DMC need reversal  logic?  Atleast , 4,1.16,1.18 follow the same format.
> >> 
> >> Packaging of firmware binary completely changed after api version 1.0, so by old firmware I want to mean
> >> the initial version before dmc 1.0.
> >
> > This kind of information really must be included in the commit message.
> > Very likely someone with old firmware will bisect to this commit, and if
> > you don't include that people need latest dmc firmware there will be
> > confusion.
> >
> > Commit message _must_ be complete and contain everything that was
> > discussed while reviewing and developing a patch.
> >
> > I added a note while merging the patch.
> > -Daniel
> >
> 
> Hi,
> 
> There is problem with gem_exec_nop throwing gpu hang with GPU HANG:
> ecode 9:0:0xfffffffe on some skls. Looks like faster ones are
> more suspectible.
> 
> My bisect pointed to this commit. As this looks like commit
> to fix the loading, one could assume that at this point the firmware
> started to actually do something.
> 
> So my failure hypothesis is that our driver runtime power well
> bookkeeping and handover to dmc is racy. Lots of speculation here but
> i suspect that during initialization, when the gpu is busy with the
> workarounds and null state batch, handover to dmc happens
> and something bad with it, like render side power toggles
> while the dmc initializes?
> 
> I haven't yet tested the redesign series for cure/clue, but changing
> the firmware from 1.19 to 1.21 makes it very hard to reproduce
> the issue.
> 
> On a related note, we need the firmware version to be part of
> error state. Also the driver could warn if not-new-enough firmware
> is found, to atleast push the unlucky bisecter to a right
> direction.

Does a revert remedy the problem?
-Daniel

> 
> - Mika
> 
> >> 
> >> >
> >> >-----Original Message-----
> >> >From: Manna, Animesh
> >> >Sent: Monday, August 3, 2015 9:56 PM
> >> >To: intel-gfx at lists.freedesktop.org
> >> >Cc: Manna, Animesh; Vetter, Daniel; Lespiau, Damien; Deak, Imre; Kamath, Sunil; Nagaraju, Vathsala
> >> >Subject: [SKL-DMC-BUGFIX 1/5] drm/i915/gen9: Removed byte swapping for csr firmware
> >> >
> >> >This patch contains the changes to remove the byte swapping logic introduced with old dmc firmware.
> >> >While debugging PC10 entry issue for skylake found with latest dmc firmware version 1.18 without byte swapping dmc is working fine and able to enter PC10.
> >> >
> >> >v1: Initial version.
> >> >
> >> >v2: Corrected firmware size during memcpy(). (Suggested by Sunil)
> >> >
> >> >Cc: Daniel Vetter <daniel.vetter at intel.com>
> >> >Cc: Damien Lespiau <damien.lespiau at intel.com>
> >> >Cc: Imre Deak <imre.deak at intel.com>
> >> >Cc: Sunil Kamath <sunil.kamath at intel.com>
> >> >Signed-off-by: Animesh Manna <animesh.manna at intel.com>
> >> >Signed-off-by: Vathsala Nagaraju <vathsala.nagaraju at intel.com>
> >> >---
> >> >  drivers/gpu/drm/i915/i915_drv.h  |  2 +-  drivers/gpu/drm/i915/intel_csr.c | 16 ++++------------
> >> >  2 files changed, 5 insertions(+), 13 deletions(-)
> >> >
> >> >diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index b94ada9..9d0ee58 100644
> >> >--- a/drivers/gpu/drm/i915/i915_drv.h
> >> >+++ b/drivers/gpu/drm/i915/i915_drv.h
> >> >@@ -742,7 +742,7 @@ enum csr_state {
> >> >  struct intel_csr {
> >> >  	const char *fw_path;
> >> >-	__be32 *dmc_payload;
> >> >+	uint32_t *dmc_payload;
> >> >  	uint32_t dmc_fw_size;
> >> >  	uint32_t mmio_count;
> >> >  	uint32_t mmioaddr[8];
> >> >diff --git a/drivers/gpu/drm/i915/intel_csr.c b/drivers/gpu/drm/i915/intel_csr.c
> >> >index 6d8a7bf..ba1ae03 100644
> >> >--- a/drivers/gpu/drm/i915/intel_csr.c
> >> >+++ b/drivers/gpu/drm/i915/intel_csr.c
> >> >@@ -244,7 +244,7 @@ void intel_csr_load_status_set(struct drm_i915_private *dev_priv,  void intel_csr_load_program(struct drm_device *dev)  {
> >> >  	struct drm_i915_private *dev_priv = dev->dev_private;
> >> >-	__be32 *payload = dev_priv->csr.dmc_payload;
> >> >+	u32 *payload = dev_priv->csr.dmc_payload;
> >> >  	uint32_t i, fw_size;
> >> >  	if (!IS_GEN9(dev)) {
> >> >@@ -256,7 +256,7 @@ void intel_csr_load_program(struct drm_device *dev)
> >> >  	fw_size = dev_priv->csr.dmc_fw_size;
> >> >  	for (i = 0; i < fw_size; i++)
> >> >  		I915_WRITE(CSR_PROGRAM_BASE + i * 4,
> >> >-			(u32 __force)payload[i]);
> >> >+			payload[i]);
> >> >  	for (i = 0; i < dev_priv->csr.mmio_count; i++) {
> >> >  		I915_WRITE(dev_priv->csr.mmioaddr[i],
> >> >@@ -279,7 +279,7 @@ static void finish_csr_load(const struct firmware *fw, void *context)
> >> >  	char substepping = intel_get_substepping(dev);
> >> >  	uint32_t dmc_offset = CSR_DEFAULT_FW_OFFSET, readcount = 0, nbytes;
> >> >  	uint32_t i;
> >> >-	__be32 *dmc_payload;
> >> >+	uint32_t *dmc_payload;
> >> >  	bool fw_loaded = false;
> >> >  	if (!fw) {
> >> >@@ -375,15 +375,7 @@ static void finish_csr_load(const struct firmware *fw, void *context)
> >> >  	}
> >> >  	dmc_payload = csr->dmc_payload;
> >> >-	for (i = 0; i < dmc_header->fw_size; i++) {
> >> >-		uint32_t *tmp = (u32 *)&fw->data[readcount + i * 4];
> >> >-		/*
> >> >-		 * The firmware payload is an array of 32 bit words stored in
> >> >-		 * little-endian format in the firmware image and programmed
> >> >-		 * as 32 bit big-endian format to memory.
> >> >-		 */
> >> >-		dmc_payload[i] = cpu_to_be32(*tmp);
> >> >-	}
> >> >+	memcpy(dmc_payload, &fw->data[readcount], nbytes);
> >> >  	/* load csr program during system boot, as needed for DC states */
> >> >  	intel_csr_load_program(dev);
> >> >--
> >> >2.0.2
> >> >
> >> 
> >> _______________________________________________
> >> Intel-gfx mailing list
> >> Intel-gfx at lists.freedesktop.org
> >> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >
> > -- 
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

More information about the Intel-gfx mailing list