Re: [PATCH] drm/amd/pm/smu7: Don't send VddC_Request on CI

On Monday, August 24, 2026 6:11:48 PM Central European Summer Time Petr 
Belyaev wrote:
> Hi,
> 
> You're right, and I withdraw the patch - hadn't considered that gating
> it off would regress the systems it was added for.
> Apologies also for the M380 claim; I thought it was VI from the commit
> message rather than checking.

Unfortunately, it is difficult to find information about which graphics card uses 
which GPU exactly, and the information online (Wikipedia, Techpowerup) is 
sometimes wrong.

> To reproduce:
> Stock 6.18.41, Bonaire XTX 1002:6658 rev 00 (XFX 1682:7260), VBIOS
> 113-260XT-HY12832-D5-2G-10, SMC firmware 11.35.0 from bonaire_smc.bin.
> DC is not enabled here (amdgpu.dc left at the default).
> I'm getting roughly 40 "failed to send message 15f ret is 0" messages
> per boot, ~1.9s each.
> gitlab: https://gitlab.freedesktop.org/drm/amd/-/work_items/5678

Thank you Petr. Let's continue the conversation on the GitLab.

> 
> On Mon, Aug 24, 2026 at 5:07 PM Timur Kristóf <[email protected]> 
wrote:
> > On Monday, August 24, 2026 4:47:14 PM Central European Summer Time Petr
> > 
> > Belyaev wrote:
> > > smu7_upload_dpm_level_enable_mask() calls
> > > smu7_apply_minimum_dce_voltage_request() unconditionally, which sends
> > > PPSMC_MSG_VddC_Request to the SMC. CI SMC firmware does not implement
> > > that message: it is only defined in smu7_ppsmc.h, tonga_ppsmc.h and
> > > fiji_ppsmc.h, and there is no CI equivalent. The SMC therefore never
> > > writes SMC_RESP, PHM_WAIT_FIELD_UNEQUAL() spins until it gives up, and
> > > every call burns the full ~1.9s response timeout.
> > 
> > Hi,
> > 
> > I'm sorry but this is wrong.
> > I added the VDDC request specifically to solve an issue with a Bonaire
> > GPU.
> > That system will boot into a black screen without requesting a high enough
> > voltage for the display engine. This patch would regress that.
> > 
> > > Nothing downstream notices, because ci_send_msg_to_smc() returns 0
> > > regardless of the outcome. The only effects are the delay and
> > > 
> > >   amdgpu: failed to send message 15f ret is 0
> > > 
> > > in dmesg. On a Radeon R7 260X (BONAIRE, 1002:6658) this is 40 messages
> > > per boot: 32 during the boot-time modeset, which becomes ~59s of blank
> > > screen, and 8 more on every DPMS wake, adding ~15s before the display
> > > comes back.
> > 
> > How do you reproduce this issue, and on which kernel version?
> > I've tested this patch on two different Bonaire chips and a Hawaii chip,
> > and haven't seen this error message. In fact I am running an R9 390X
> > right now and I don't see this error message in my logs.
> > 
> > > Commit 0138610c1413 ("drm/amd/pm/smu7: Fix SMU7 voltage dependency on
> > > display clock") extended this feature to CI, which the previous
> > > implementation had deliberately excluded -- the old call site was
> > > guarded by pp_table_version == PP_TABLE_V1 with an adjacent comment
> > > reading "TO DO for v0 iceland and Ci". That commit was verified on a
> > > Radeon R9 M380, which is VI, so the CI path went untested.
> > 
> > The CI path definitely did not go untested.
> > R9 M380 is Bonaire (it's in an old iMac).
> > You can see all the details here:
> > https://gitlab.freedesktop.org/drm/amd/-/work_items/3425#note_3338643
> > 
> > Best regards,
> > Timur