linux-kernel - RE: [PATCH v1 2/4] drm/hyperv: Don't forget to put PCI device when removing conflicting FB fails

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Date:   Tue, 23 Aug 2022 09:19:54 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     "Michael Kelley (LINUX)" <mikelley@...rosoft.com>,
        "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        Wei Liu <wei.liu@...nel.org>,
        Deepak Rawat <drawat.floss@...il.com>,
        KY Srinivasan <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        Dexuan Cui <decui@...rosoft.com>
Subject: RE: [PATCH v1 2/4] drm/hyperv: Don't forget to put PCI device when
 removing conflicting FB fails

"Michael Kelley (LINUX)" <mikelley@...rosoft.com> writes:

> From: Vitaly Kuznetsov <vkuznets@...hat.com> Sent: Thursday, August 18, 2022 7:25 AM
>> 
>> When drm_aperture_remove_conflicting_pci_framebuffers() fails, 'pdev'
>> needs to be released with pci_dev_put().
>> 
>> Fixes: 76c56a5affeb ("drm/hyperv: Add DRM driver for hyperv synthetic video device")
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
>> ---
>>  drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
>> b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
>> index 46f6c454b820..ca4e517b95ca 100644
>> --- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
>> +++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
>> @@ -82,7 +82,7 @@ static int hyperv_setup_gen1(struct hyperv_drm_device *hv)
>>  	ret = drm_aperture_remove_conflicting_pci_framebuffers(pdev,
>> &hyperv_driver);
>>  	if (ret) {
>>  		drm_err(dev, "Not able to remove boot fb\n");
>> -		return ret;
>> +		goto error;
>>  	}
>> 
>>  	if (pci_request_region(pdev, 0, DRIVER_NAME) != 0)
>> --
>> 2.37.1
>
> This patch appears to be obsoleted by commit a0ab5abced55
> that was merged into 6.0-rc1.  Of course, it does beg the question of
> why the original function hyperv_setup_gen2(), which is now renamed
> to hyperv_setup_vram(), doesn't check the return value from
> drm_aperture_remove_conflicting_framebuffers().

AFAICT this commit (which I've obviously missed) also solves the worst
issue I'm trying to address with this series: conflict between
framebuffer and SR-IOV VF config space. It would probably still make
sense to reserve the whole FB region on Gen1 first thing and use it
as-is for DRM/FB later (Patches 3-4).

-- 
Vitaly