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Wed, 29 Apr 2026 06:40:07 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id pAzhHcen8WnhXwAAD6G6ig (envelope-from ); Wed, 29 Apr 2026 06:40:07 +0000 Message-ID: Date: Wed, 29 Apr 2026 08:40:07 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: further issues with MGA G200 graphics chipset To: stuart hayes , Jacob Keller , Jocelyn Falempe , "airlied@redhat.com" Cc: dri-devel@lists.freedesktop.org, "linux-kernel@vger.kernel.org" , Pasi Vaananen References: <76aba88d-ec23-4b3c-ad91-83face0c3e94@intel.com> <6ec01703-31e0-4998-9508-a5a115ae7bc9@intel.com> <14aa4840-29c4-46df-b60d-8e1b92494ad2@redhat.com> <5155f29b-bc4d-4e60-9a26-22d568c43e46@redhat.com> <0be82b55-0f78-4ef9-8b50-f068ec36ec4f@suse.de> <3def4337-4297-45fa-8825-4147abda49f4@suse.de> Content-Language: en-US From: Thomas Zimmermann Autocrypt: addr=tzimmermann@suse.de; keydata= xsBNBFs50uABCADEHPidWt974CaxBVbrIBwqcq/WURinJ3+2WlIrKWspiP83vfZKaXhFYsdg XH47fDVbPPj+d6tQrw5lPQCyqjwrCPYnq3WlIBnGPJ4/jreTL6V+qfKRDlGLWFjZcsrPJGE0 BeB5BbqP5erN1qylK9i3gPoQjXGhpBpQYwRrEyQyjuvk+Ev0K1Jc5tVDeJAuau3TGNgah4Yc hdHm3bkPjz9EErV85RwvImQ1dptvx6s7xzwXTgGAsaYZsL8WCwDaTuqFa1d1jjlaxg6+tZsB 9GluwvIhSezPgnEmimZDkGnZRRSFiGP8yjqTjjWuf0bSj5rUnTGiyLyRZRNGcXmu6hjlABEB AAHNJ1Rob21hcyBaaW1tZXJtYW5uIDx0emltbWVybWFubkBzdXNlLmRlPsLAjgQTAQgAOAIb AwULCQgHAgYVCgkICwIEFgIDAQIeAQIXgBYhBHIX+6yM6c9jRKFo5WgNwR1TC3ojBQJftODH AAoJEGgNwR1TC3ojx1wH/0hKGWugiqDgLNXLRD/4TfHBEKmxIrmfu9Z5t7vwUKfwhFL6hqvo lXPJJKQpQ2z8+X2vZm/slsLn7J1yjrOsoJhKABDi+3QWWSGkaGwRJAdPVVyJMfJRNNNIKwVb U6B1BkX2XDKDGffF4TxlOpSQzdtNI/9gleOoUA8+jy8knnDYzjBNOZqLG2FuTdicBXblz0Mf vg41gd9kCwYXDnD91rJU8tzylXv03E75NCaTxTM+FBXPmsAVYQ4GYhhgFt8S2UWMoaaABLDe 7l5FdnLdDEcbmd8uLU2CaG4W2cLrUaI4jz2XbkcPQkqTQ3EB67hYkjiEE6Zy3ggOitiQGcqp j//OwE0EWznS4AEIAMYmP4M/V+T5RY5at/g7rUdNsLhWv1APYrh9RQefODYHrNRHUE9eosYb T6XMryR9hT8XlGOYRwKWwiQBoWSDiTMo/Xi29jUnn4BXfI2px2DTXwc22LKtLAgTRjP+qbU6 3Y0xnQN29UGDbYgyyK51DW3H0If2a3JNsheAAK+Xc9baj0LGIc8T9uiEWHBnCH+RdhgATnWW GKdDegUR5BkDfDg5O/FISymJBHx2Dyoklv5g4BzkgqTqwmaYzsl8UxZKvbaxq0zbehDda8lv hFXodNFMAgTLJlLuDYOGLK2AwbrS3Sp0AEbkpdJBb44qVlGm5bApZouHeJ/+n+7r12+lqdsA EQEAAcLAdgQYAQgAIAIbDBYhBHIX+6yM6c9jRKFo5WgNwR1TC3ojBQJftOH6AAoJEGgNwR1T C3ojVSkIALpAPkIJPQoURPb1VWjh34l0HlglmYHvZszJWTXYwavHR8+k6Baa6H7ufXNQtThR yIxJrQLW6rV5lm7TjhffEhxVCn37+cg0zZ3j7zIsSS0rx/aMwi6VhFJA5hfn3T0TtrijKP4A SAQO9xD1Zk9/61JWk8OysuIh7MXkl0fxbRKWE93XeQBhIJHQfnc+YBLprdnxR446Sh8Wn/2D Ya8cavuWf2zrB6cZurs048xe0UbSW5AOSo4V9M0jzYI4nZqTmPxYyXbm30Kvmz0rYVRaitYJ 4kyYYMhuULvrJDMjZRvaNe52tkKAvMevcGdt38H4KSVXAylqyQOW5zvPc4/sq9c= In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Score: -2.80 X-Spam-Level: X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; TO_DN_EQ_ADDR_SOME(0.00)[]; TAGGED_RCPT(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_TO(0.00)[gmail.com,intel.com,redhat.com]; MID_RHS_MATCH_FROM(0.00)[]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_SEVEN(0.00)[7]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:mid,imap1.dmz-prg2.suse.org:helo,suse.com:url] X-Spam-Flag: NO Hi Am 28.04.26 um 21:12 schrieb stuart hayes: > On 4/27/2026 7:14 AM, Thomas Zimmermann wrote: >> Hi >> >> Am 25.04.26 um 01:29 schrieb Jacob Keller: >> [...] >>>> >>>> So I suggest to pick Manufacturer, Product, Version as key. I'd be >>>> surprised if we find more than a hand full of systems with the >>>> issue. If >>>> we see a trend or common pattern, we can generalize later on. >>>> >>> I think this is the best solution. Keep it focused for now. I believe >>> Intel has two major platforms that we care about with respect to this >>> issue. I'll see if I can dig up the data. The systems install the MGA >>> G200 for BMC use but don't seem to expose the VGA connection. >>> >>> For the specific system I have that was faulty, we have the following: >>> >>> $ for t in system-manufacturer system-product-name system-version ; \ >>>      do dmidecode -s ${t}; \ >>> done >>> Dell Inc. >>> PowerEdge XR8720t >>> Not Specified >>> >>> >>> >>> I believe there was also some concern about HP systems which similarly >>> use this chipset, but I don't have the DMI data for that one off hand. >>> I've asked some colleagues to confirm the situation and obtain that >>> data. I'll get back early next week if we think there are any other >>> systems possibly affected. >>> >>> In the mean time, I'm happy to have our team test any patch to confirm >>> that it behaves as expected and resolves the service interruptions. >> >> For now, I've modified the two places that have BMC support in the >> driver. Could you please also tell me your system's exact Matrox >> chipset or its PCI id? >> >> The patch is attached for your testing. It would work against drm-tip >> or v7.1-rc1. >> >> I've also found the page at [1], which claims that there's a Mini-DP >> port at the front. If so, I'd assume that there's also an extra >> encoder chip to replace the VGA. If we ever get specs for that, we >> could implement real support in the driver. >> >> In the meantime, the current fix should work. In the worst case, that >> Mini-DP port would give a lower default resolution. >> >> [1] https://www.dell.com/en-us/shop/ipovw/poweredge-xr8720t? >> hve=shop+now#techspecs_section >> >> Best regards >> Thomas >> >> > > So this patch disables DDC polling if the dmi_check_system() matches. > If this was to happen on systems that _do_ have a physical VGA > connector, will that port still be active, just with a resolution that > may not be compatible with the monitor that's plugged in? The DMI test is supposed to only match on affected systems. If there's a matched system with a VGA port, or possibly that Mini-DP port, users will get a number of bogus display modes at the worst. But the default mode is 1024x768, which should work on any display. > > I don't see anyone say that the DDC polling doesn't cause too much > latency for real time kernels on other systems that do have a VGA > connector... did I miss that, or is there a chance that a lot of other > systems that use this driver might also have issues with a real time > kernel? That missing VGA port is a problem on any workload. So we fix it as far as possible. Where the connector polling interferes with RT, it can also be disabled with drm_kms_helper.poll=0. Best regards Thomas > > >> >> >>> >>> Appreciate all the feedback on this thread. >>> >>> Thanks, >>> Jake >> > -- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)